Food Safety and Food Technology

Introduction
• Consumers in the U.S. and Canada enjoy food supplies among the safest, most pleasing, and most abundant in the world
– With this benefit comes the consumer's responsibility to distinguish between paths leading to food safety and those that pose a hazard

• Safety
– The practical certainty that injury will not result from the use of a substance
• Hazard
– A state of danger
– Used to refer to any circumstance in which harm is possible under normal conditions of use

• FDA's ongoing areas of concern regarding our food supply
– Microbial food borne illness
–
• Constitute a hazard whenever people consume single foods either by choice or necessity
– Residues in food
• Environmental contaminant
• Pesticides
• Animal drugs
– Nutrients in foods
• More and more artificially constituted foods are appearing on the market
– Intentional food additives
• Of little concern because so much is known about them that they pose virtually no hazard to consumers and because their use is well regulated
– Genetic modification of food

• Microbial food borne illness
– Commonly called food poisoning
– Transmitted to human beings through food and water
– Caused by an infectious agent (food borne infection) or a poisonous substance (food intoxication)
– Episodes far outnumber any other kind of food contamination

• Food supply and terrorism
– FDA's strategies for counter terrorism
• Awareness
• Prevention
• Preparedness
• Response
• Recovery
– USDA has created a Food Biosecurity
Action team to protect agriculture and other aspects of the food supply

Microbes and Food Safety
• Microbes
– A shortened name for microorganisms
– Minute organisms too small to observe without a microscope
• Including bacteria, viruses, and others
• Food borne illnesses can be life threatening
– Are increasingly unresponsive to standard antibiotics
• Even normally mild food borne illnesses can be lethal for people who
– Are ill or malnourished
– Have a compromised immune system
– Are in an institution
– Have liver or stomach illnesses
– Are pregnant, very old, or very young
• Each year in the United States, an estimated 76 million people become ill from food borne diseases
– ˜5,000 of them die
• Because of improved safety procedures adopted by food producers, disease from at least 5 problem organisms is on the decline
• If digestive tract disturbances are the only major symptom of your next bout of "stomach flu" chances are excellent that what you really have is a food borne illness
• Get medical help if these symptoms occur
– Bloody stools
– Diarrhea of more than 3 days' duration
– Fever of longer than 24 hours duration
– Headache accompanied by muscle stiffness and fever
– Numbness, muscle weakness, tingling sensations in the skin
– Rapid heart rate, fainting, dizziness

How Do Microbes in Food Cause Illness in the Body?
• Microorganisms can cause food borne illness by either infection or intoxication
• Infection
– Infectious agents infect and multiply in the tissues of the body
• Intoxication
– Some microorganisms in foods produce
• Enterotoxins
– Poisons that act upon mucous membranes
• Neurotoxins
– Poisons that act upon the cells of the nervous system
• In intoxication, the toxins may arise
– In food during improper preparation or storage
– Within the digestive tract after a person eats contaminated food

• Staphylococcus aureus
– Most common source of food toxicity

• Clostridium botulinum
– Most infamous source of food toxicity
– Toxin produced under anaerobic conditions
– Botulism quickly paralyses muscles
• Death can occur within 24 hours
– Survivors may suffer the effects for months or years
– Botulinum toxin is destroyed by heat
• Foods that contain the toxin can be rendered harmless by boiling them for 10 minutes
• Warning signs of botulism
– Difficulty breathing
– Difficulty swallowing
– Double vision
– Weak muscles

Food Safety from Farm to Table
• Careful food handling is required to prevent microbes from becoming a problem
– The globalisation of the U.S. food supply has widened safety concerns in farming, processing, and transportation
– Equally critical to the chain of food safety is the final handling of food by people who purchase it and consume it at home

• Majority of food poisoning cases
– Result of errors consumers make in handling foods after purchase
– Commercially prepared food is usually safe
• Accidents do occur and often affect many people at once
– Dairy farmers rely on pasteurisation
• A process of heating milk to kill many disease causing organisms and make the milk safe for consumption

• Attention on E. coli
– In the mid-1990s a fast food restaurant chain in the Northwest served undercooked hamburgers from meat contaminated wit the dangerous bacterium E. coli 0157:H7
• 4 people died
• 100s of patrons were stricken with serious illness

• Two important safety issues
– Raw meats routinely contain live, disease causing organisms of many types
– Thorough cooking is necessary to make animal derived foods safe

• Infections from E. coli 0157:H7
– Symptoms
• Bloody diarrhea
• Severe intestinal cramps
• Dehydration
• In the worst cases, Hemolytic uremic syndrome leads to abnormal blood clotting with kidney failure, damage to the central nervous system and other organs, and death

• Symptoms set in a few days after eating tainted meat, raw milk, fresh berries or organic produce that has been contaminated
• Treatment
– Children given antibiotics were 7x more likely to to develop hemolytic uremic syndrome
• The drug seems to make the bacterial toxin more available for absorption, so it reaches higher concentrations in body tissues

• Industry Controls Government Inspections and HACCP
– The USDA plays a primary role in inspecting and regulating foods
• A USDA inspector monitors U.S. meat processing plants every day
– Ensure that they meet government standards
• Budget constraints do not allow for such thorough inspections of seafood, egg, produce, or processed food facilities
– May receive only one inspection every five years on average

• By law, U.S. producers and handlers of meat, poultry, seafood, fresh fruit, and vegetable juices must employ a Hazard Analysis Critical Control Point (HACCP) plan
– A systematic plan to identify and correct potential microbial hazards in the manufacturing, distribution, and commercial use of food products

• Since the implementation of the HACCP system U.S. contamination of
– Poultry has declined by almost 50%
– Ground beef has declined by almost 40%
– Pork has declined by almost 25%

• Consumer Protection
– The safety of canned and packaged foods sold in grocery stores is controlled through sound food technology practices
– Rare accidents do happen
• Batch numbering enables the recall of contaminated foods through public announcements
• The FDA monitors large food suppliers and importers

• Protect yourself
– Inspect the seals and wrappers of packages
– Reject open, leaking, or bulging cans, jars, and packages
– A badly dented can or mangled package is useless in protecting food
– Frozen foods should be solidly frozen
• Those in a chest type freezer should be stored below the frost line

• Myths that often make consumers sick
– "If it tastes okay, it's safe to eat."
– "We have always handled our food this way, and nothing has ever happened."
– "I sampled it a couple of hours ago and didn't get sick, so it's safe to eat."

Food Safety in the Kitchen
• Large scale commercial incidents make up only a fraction of the nation's total food poisoning cases each year
• The vast majority of cases arise from one person's error in a small setting
– Affect just a few victims

• Food can provide ideal conditions for bacteria to thrive or produce toxins
– Disease causing bacteria require
• Warmth
– 40°F 140°F = 4°C 60°C
• Moisture
• Nutrients

• To defeat bacteria
– Keep hot food hot
– Keep cold food cold
– Keep raw foods separate
– Keep your hands and the kitchen clean

• Keep Hot Food Hot
– Cook foods long enough to reach an internal temperature that will kill microbes
– After cooking, foods must be held at 140°F or higher until served
• Cooking does not destroy all bacterial toxins
– Even hot cooked foods, if handled improperly prior to serving, can cause illness
– After the meal, cooked foods should be refrigerated immediately or within two hours at the maximum

• Keep Cold Food Cold
– Start when you leave the grocery store
– Upon arrival home, load foods into the refrigerator or freezer immediately
– Applies to defrosting foods
• Thaw meats or poultry in the refrigerator
• Marinate meats in the refrigerator

• Any food with an "off" appearance or odour should not be used or even tasted
• You cannot rely on your senses of smell and sight alone to warn you
– Most hazards are not detectable by odour, taste, or appearance

• Keep Raw Foods Separate
– Prevent cross contamination of foods
• The contamination of foods through exposure to utensils, hands, or other surfaces that were previously in contact with contaminated food
• Raw foods, especially meats, eggs and seafood, are likely to contain bacteria
• To prevent them from spreading
– Keep the raw foods and their juices away from ready to eat foods
– After handling raw foods wash surfaces, including your hands, thoroughly with soap before that surface contacts cooked foods or foods that are eaten raw

• Keep Your Hands and the Kitchen Clean
– Requires
• Using freshly washed utensils
• Laundered towels
• Washing your hands properly
– Remember to use a nailbrush to clean under fingernails when washing hands and tend to routine nail care
– Artificial nails, long nails, and chipped polish harbor more bacteria than do natural, clean, short nails

• For most purposes, washing hands with ordinary soap and warm water is
effective
– Using an alcohol based hand sanitising gel can provide additional killing power against many remaining bacteria and most viruses
• Such use provides additional protection against spreading illnesses or when someone in the house is ill or when preparing food for an infant, the elderly, or people with compromised immune systems
• If you are ill, or have open sores, stay away from food preparation
• Microbes nestle down in small, damp spaces such as
– The inner cells of sponges
– The pores between the fibres of wooden cutting boards
• Little science supports the use of antibacterial cleaners, sponges, cloths, boards, or utensils
• Disposable cutting boards
– Expensive
– Add to the environmental burden of trash
• Ensure the safety of regular cutting boards and reduce the microbes in sponges by washing them in the dishwasher

• To eliminate microbes in your kitchen
– Poison the microbes on cutting boards, sponges, and other equipment with toxic chemicals such as bleach
• Benefit: chlorine can kill even the hardiest organisms
• Drawback: chlorine is toxic to handle, can ruin clothing, and washes down household drains into the water supply and forms chemicals that can harm waterways and fish
• Treat kitchen utensils with heat
– Soapy water heated to 140°F kills most harmful organisms and washes most others away
– Water must be scalding hot, well beyond the temperature of the tap
• Automatic dishwasher
– Washes in water hotter than hands can tolerate
– Most dishwasher detergents contain chlorine
• For sponges
– Place the wet sponge in a microwave and heat it until steaming hot

Which Foods Are Most Likely to Make People Sick?
• Some foods are more hospitable to microbial growth than others
• Especially hospitable foods:
– Foods that are high in moisture and nutrients
– Foods that are chopped or ground

• Meats and Poultry
– Require special handling
• Packages bear labels to instruct consumers on meat safety
– Meats in the grocery cooler often contain
all sorts of bacteria
• Meats provide a moist, nutritious environment that is just right for microbial growth
• Ground meat or poultry is handled more than meats left whole
– Grinding exposes much more surface area for bacteria to land on
– Experts advise cooking these foods to well done
• Use a thermometer to test the internal temperature of poultry and meats before declaring them done
– Burgers often turn brown and appear cooked before their internal temperature is high enough to kill harmful bacteria

• Bovine Spongiform Encephalopathy (BSE)
– Though unrelated to sanitation, animal diseases pose a worry for meat eaters
– A disease of cattle
– Linked with a rare but invariably fatal human brain disorder
• Observed in people who consume products from infected animals
• To date: Fewer than 150 people, most of them in Great Britain, have been diagnosed with or are suspected of having the disease
• BSE is among a handful of diseases caused by an oddly shaped protein, known as a prion
– An infective agent consisting of an unusually folded protein that disrupts normal cell functioning, causing disease
– Seem to lie dormant in the body for many years before their deadly symptoms arise

• Prions
– Are not living
– Cannot be killed or controlled through cooking or disinfecting
– The body's immune system fails to mount defensive actions against them
– Little is known about how prions cause diseases or how to treat people who develop them

• The prion responsible for BSE concentrates in the nervous and digestive tissues of infected animals
– People living in or traveling to areas reporting BSE should avoid foods such as
• Sausages
• Ground meats
• Chopped meats
• In cattle, the infection probably spreads though the now-banned practice of enriching cattle feed with nutrients derived from cattle brains, blood, or other tissues

• The USDA has enacted protective measures targeting BSE
– Prohibiting the use of "downer" cattle for human consumption
– Increasing BSE testing of cattle at slaughter
– Other protective measures
• One substantial risk remains
– Imported supplements made from glands of animals
– Often sold as hormone preparations

• Eggs
– Raw, unpasteurised eggs are likely to be contaminated by Salmonella bacteria
• Salmonella of a most virulent type has been detected in blood from food poisoning victims and samples of illness causing foods that contain raw eggs
• To reduce incidence the FDA requires egg cartons to carry instruction labels urging consumers to keep eggs refrigerated, cook eggs until yolks are firm, and cook foods containing eggs thoroughly

• Healthy people can safely enjoy foods that call for raw or undercooked eggs by preparing them with pasteurised egg substitutes
– Even raw pasteurised egg substitutes may contain a few live bacteria that escape the pasteurisation process
• So they may not be safe for pregnant women, the elderly, the very young, or those suffering from immune dysfunction
• Raw Produce
– Fruits and vegetables can present a microbial threat unless they are thoroughly rinsed in running cold water to remove microbes before peeling, chopping, or eating
– Just ten years ago, meats, eggs, and seafood posed the greatest food borne illness threat
• Today produce equals them
– Especially troublesome are foods consumed raw and that grow close to the ground
• Making bacterial contamination from the soil and organic fertilisers likely
• Much produce is imported from countries
– Where farmers may not adhere to sanitary growing and harvesting procedures
– Where contagious diseases are widespread in the population
– Fields may be irrigated with unclean water
– Crops may be fertilised with untreated animal or human manure
– Produce may be picked by infected farm workers with poor hygiene practices
• Rough skins of melons provide crevices that harbor bacteria
– Should be scrubbed with a brush under running water before peeling or cutting
• All produce should be rinsed thoroughly under running water for at least 10 seconds
• Unpasteurised or raw juices and ciders are not safe because microbes on the original fruit may multiply
• Sprouts are often eaten raw in salads, wraps, and other sandwiches
– No sure way exists to make sprouts safe except to cook them
– Sprout seeds may harbor E. coli O157:H7 bacteria that cannot be washed away
• Rinsing sprouts does not ensure their safety from E. coli or Salmonella organisms

• Seafood
– A variety of microbial dangers may lurk in even normal appearing seafood
• Viral hepatitis
• Worms
• Flukes
• Other parasites
• Viruses that can cause severe intestinal disorders
• Naturally occurring toxins

• Hepatitis infection causes prolonged illness that
– Persists for months or years
– Severely damages the liver
– Greatly increases the risk of developing liver cancer
– Once in the body, is transmissible to others

• Many types of worms depend on the blood of their host for food and reproduction
– They attack digestive membranes
• Sometimes causing life threatening perforations
– Flukes attack and damage the liver

• Dangers posed by seafood have grown in recent years
– As population density increases along the seashore, the offshore waters are becoming more polluted, contaminating the seafood living there
• Viruses that cause human diseases have been detected in ˜90% of water off the U.S. coast
– Watchdog agencies monitor commercial fishing areas to keep harvesters out of unsafe waters
• Unwholesome food can still reach the market
• People who have enjoyed raw oysters and other raw seafood for years may be tempted to ignore threats because they have never experienced serious illness
– It is not true that alcoholic beverages taken with raw seafood eliminate risks or that hot sauce kills the bacteria
– The risks of eating raw or lightly cooked seafood today are unacceptably high due to environmental contamination
• Adults and children should refrain from eating raw sushi or lightly steamed seafood
– Even when the food is prepared by an expert master chef
– Not all varieties of sushi are made from raw fish
• Freezing fish to make it safe to eat is only partly effective
– Freezing will kill mature parasitic worms
– Only cooking can kill all worm eggs and other microorganisms that can cause illness

• Honey
– Can contain dormant spores of Clostridium botulinum that can awaken in the human body
– Produce the botulinum toxin
• Mature adults are usually protected against this threat
• Infants under one year of age should never be fed honey
– Which can also be contaminated with environmental pollutants picked up by the bees

• Picnics, Lunch Bags, And Take Out Foods
– Choose foods that remain safe to eat without refrigeration
– Carry foods that do well at environmental temperatures for only an hour or two in a cooler or thermal lunch bag
• To keep bag foods chilled
– Choose a thermal lunch bag and freeze beverages to pack in with foods
– Prepackaged single servings promoted as lunch foods
• Keep well
• Can be high in saturated fat and sodium
• Often cost 2x-3x the price of foods purchased separately
• Excessive packaging adds to waste disposal problem

• Takeout foods
– Be certain that the food is safe when you buy it
– Leftover portions of restaurant meals
• Reheat thoroughly (to 140°F) before eating
• Discard any portion held at room temperature for longer than two hours from the time it first appears on the table until you place it in your refrigerator at home

How Can I Avoid Illness When Traveling?
• People who travel to places where cleanliness standards are lacking have a 50-50 chance of contracting a food borne illness
– Commonly known as traveler's diarrhea
• To avoid food borne illness while traveling
– Before you travel, as your physician which medicines to take with you in case you get sick
– Wash your hands often with soap and water
• Especially before handling food or eating
• Eat only cooked and canned foods
– Eat raw fruits and vegetables only if you have washed them with your own clean hands in boiled water and peeled them yourself
– Skip salads
• Beware that water, ice, and beverages made from water may be unsafe
– Take along disinfecting tablets or an element that boils water in a cup
– Drink only treated, boiled, canned, or bottled beverages
• Drink them without ice
– Avoid using the local water unless you boil or disinfect it first
• Even if you are brushing your teeth
• Be aware that mad cow disease poses an extremely small risk (1 in 10 billion servings) to travelers to countries where BSE is a problem
– To err on the safe side, avoid eating beef altogether or select solid pieces of muscle meat that are less likely to be contaminated
• In general, remember these rules
– Boil it, cook it, peel it, or forget it

Natural Toxins in Foods
• Humans rarely suffer actual harm from such poisons
– But the potential for harm does exist
• Belladonna and hemlock
– Have reputations as deadly poisons
• Sassafras
– Contains a cancer causing agent
– Banned from use in commercially produced foods and beverages
• Cabbage, turnips, mustard greens, and radishes
– Contain small quantities of goitrogens
• Compounds that can enlarge the thyroid gland and aggravate thyroid problems
• Effects show up only under extreme conditions when people have little but cabbage to eat
– Ordinarily, cabbage and their relatives are celebrated for their nutrients and phytochemicals associated with low cancer rates
• Raw lima beans, cassava, fruit seeds such as apricot pits
– Contain cyanogens, precursors to cyanide
• Many countries restrict commercially grown lima beans to those varieties with the lowest cyanogen contents
• Most cassava has only small amounts of cyanogens
– The amount in bitter varieties can be exceedingly high and poses a threat to hungry people who consume them to escape starvation
• Fruit seeds are seldom deliberately eaten
– An occasional swallowed seed or two presents no danger
• Potatoes
– Contain many natural poisons, including solanine
• A powerful, bitter, narcotic like substance
• The small amounts normally found in potatoes are harmless
• Solanine can build up to toxic levels when potatoes are exposed to light during storage
• Not destroyed by cooking
• Most found in a green layer that develops just below the skin that can be peeled off
– If the potato tastes bitter throw it out
• Seafood
– At certain times of the year may become contaminated with the so-called red tide toxin that occurs during algae blooms
• Eating seafood contaminated with the red tide causes a form of food poisoning that paralyses the eater
• Potential Benefits
– Kills almost all disease producing microorganisms present in food
• A characteristic that has earned irradiation the alternative name cold pasteurisation
– Has no effect on most toxins, prions, and microbial spores
– Raw poultry emerges from irradiation 99.9% free of disease causing microorganisms
• Reduces the risk of cross contamination

Consumer Corner: Irradiation and Food Safety
• Eliminates the need to quarantine and spray fresh produce with pesticides before shipping to prevent the spread of plant diseases or harmful insects and their eggs
– Kills mould spores
• Replacing fungicides now sprayed on harvested foods
– Slows decay in fruits and vegetables
• Making them last longer and appear fresher
• Reduces the incidence of food borne illness
• Reduces the destruction of food by pests and decay
• Irradiation facilities are expensive to build
– Placing them out of reach for the world's impoverished people who most need them

• The Irradiation Process
– Works by exposing foods to controlled doses of gamma rays from the radioactive compound cobalt 60
• As radiation passes through living cells, it disrupts their internal structures and kills or deactivates the cells

• Low doses of radiation
– Can kill the growth cells in the "eyes" of potatoes and onions
• Preventing them from sprouting
– Delay ripening of bananas, avocados, and other fruits

• High doses
– Can penetrate tough insect exoskeletons and mold or bacterial cell walls
• To destroy their life maintaining DNA, proteins, and other molecules
– Can kill most microbes even while food is in a frozen state
• Making irradiation uniquely useful in protecting foods such as whole turkeys that are ordinarily marketed frozen

• Doses of radiation used on foods compared with the lethal human dose
– The lowest doses of radiation needed to delay ripening and sprouting of fragile fruits and vegetables are 10x-20x higher than the doses that would kill human beings
– The dose required to sterilise foods is many times higher
• With the exception of dried herbs and spices, most foods are not completely sterilised because that would destroy the food

• Labeling of Irradiated Foods
– Required by the FDA
• Irradiated foods bear a label, in letters as large as those of the ingredients list, stating that the foods have been treated with radiation
• Display the irradiation symbol
– AKA. radura logo
• Labeling of Irradiated Foods
– No label is required for foods containing irradiated ingredients and for irradiated foods served in restaurants

• If Irradiation Is So Great, Why Aren't More Foods Irradiated?
– Cost
• Cost more to produce and package that conventionally processed foods
– Consumer acceptance
• Changes the flavour of food somewhat
– Most consumers have not tasted enough irradiated foods to know whether they dislike them or not
• Consumer fears about safety
– Foods will become radioactive
• Properly irradiated food does not become radioactive
– Foods will lose substantial nutrients during irradiation
– Irradiated foods are not safe to eat
– Harmful chemicals are formed during irradiation
– Radioactive substances used to irradiate foods will endanger plant workers, the general population, and the environment

• Irradiation's Effects on Nutrients
– Most nutrients, such as proteins, fats, carbohydrates, and minerals, survive irradiation intact or sustain insignificant losses
– Nutrients sensitive to heat treatment, such as the B vitamins and ascorbic acid, are sensitive to irradiation
• Substantial loses occur even with high doses of radiation well beyond those permitted in the treatment of food
• In general, nutrient loses sustained during irradiation are similar to those caused by canning or cooking
• The FDA deems nutrient losses of less than 2% of the total as insignificant
– Most losses incurred through irradiation fall within this limit
• Irradiation Safety
– More than 40 years of research on animals have revealed no toxic effects from eating irradiated foods
– Decades ago studies of human volunteers who ate a diet composed entirely of irradiated foods found no ill effects
• Radiolytic products formed during irradiation are commonly formed in foods during many forms of processing
– Among them are minuscule amounts of free radicals that could be damaging to health
– These tiny amounts are unlikely to pose a hazard to the body
• Whose antioxidant systems are equipped to neutralise free radicals from many sources
• The process necessitates transporting radioactive materials, training workers to handle them safely, and then disposing of the spent wastes which remain radioactive for many years

• Opponents of irradiation worry that workers could be exposed to nonlethal low doses of radiation that could conceivably cause ill effects
– The food industry strives to safeguard both workers and consumers through strict operating standards and compliance with regulations

• Some consumers worry that food manufacturers might use the technology unethically
– Current law prohibits the sale of old or tainted foods found to have high bacterial counts, usually from insect or rodent droppings
– The FDA condemn such foods and orders their destruction
• Unscrupulous manufacturers could irradiate old or tainted food and then sell the food as wholesome to unsuspecting consumers
• Consumers: The Final Authority
– Only a few irradiated products are now available for use
– Irradiated ground beef products are approved for U.S. school lunch programs
• The higher cost of these products discourages many schools from using them
• Schools that do use them are encouraged to inform students and parents about the products
• Whether more irradiated foods will appear in markets depends largely upon whether consumers choose to buy them
• According to a national survey of supermarket shoppers, the proportion of those willing to purchase irradiated foods declined during the past decade from 70% to about 50%
– Cost is a factor
• In the end, acceptance may depend on taste
– flavour is high on most consumers' food priorities
– Irradiation changes the taste of food slightly

Residues and Contaminants in Foods
Pesticides
• Pesticides
– Chemicals used to control insects, diseases, weeds, fungi, and other pests on crops and around animals
– Used broadly, the term includes herbicides, insecticides, and fungicides
• Used to ensure the survival of food crops
– Damage to the environment is considerable and increasing
• There is some question about whether the widespread use of pesticides has really improved the overall yield of food
– Even with the extensive pesticide use, the world's farmers lose large quantities of their crops to pests every year
• Accumulate in the food chain
• Kill pests' natural predators
• Pollute the water, soil, and air
• Each years in the U.S., 4.5 billion pounds of pesticides are applied
– To kill pests around homes
– To control pests in gardens
– To reduce farm loss to insects
– To preserve wood products
– To cure lie, scabies, worms, and other parasites in people and their pets
– To repel mosquitoes and other biting insects
– Etc.
• Do Pesticides on Foods Pose a Hazard to Consumers?
– Many pesticides are broad spectrum poisons that damage all living cells
• Not just those of pests
• Their use poses hazards to the plants and animals in natural systems
– Especially to workers involved with pesticide production, transport, and application
• High doses of pesticides applied to laboratory animals cause
– Birth defects
– Sterility
– Tumours
– Organ damage
– Central nervous system impairment
• Equivalent doses are unlikely to occur in humans
• Pesticide residues on agricultural crops can survive processing and may be present in and on foods served to people
• Government agencies in the U.S. and Canada monitor pesticide safety and residues on foods to ensure minimal risk to the consumer
• Infants and children may be more susceptible to adverse effects
• Their brains cannot exclude pesticides and other chemicals to the same extent as the adult brain
– Many pesticides work by interfering with normal nerve and brain chemistry
• The effects of chronic low dose exposure to pesticides on the developing human brain are largely unknown
• Children may be exposed to pesticides through normal behavior such as:
– playing outside on treated soil or lawns;
– handling sticks, rocks, and other potentially contaminated objects;
– crawling on treated carpets, furniture, and floors,
– placing fingers and other objects in the mouth;
– seldom washing their hands;
– eating with their fingers
• Children eat proportionally more food per pound of body weight than do adults
– Traces of pesticides present on foods can build up quickly in their small bodies
• Compared with other sources of pesticides, the traces found on food rarely exceed safe limits
– Most of those present can be removed by washing produce and following other guidelines

• Regulation of Pesticides
– Tolerance limit
• The maximum amount of a residue permitted in a food when a pesticide is used according to label directions
• Legal tolerance limits are low
– Generally 1/100 to 1/1,000 of the level found to cause no effect in laboratory animals
• If a pesticide is misused, growers risk fines, lawsuits, and destruction of their crops
• In 25 years of testing, the FDA has seldom found crop residues above tolerance levels
• A loophole in federal regulations allows companies in the U.S. to make banned pesticides and export them to other countries
– The banned pesticides can then return the the U.S. on imported foods
• The majority of both imported and domestic foods tested by the FDA are found to contain either no residues or residues within federally permitted limits

• Too few foods are being tested
– Budget constrains limit the FDA's testing capacity
• Possible Alternatives to Pesticides
– Some pesticides promote the survival of the very pests they are intended to wipe out
• A pesticide aimed at a certain insect may kill almost 100% of them, but due to genetic variability a few individuals are likely to survive exposure
– These resistant insects will then produce offspring that have inherited resistance to the pesticide
• To control these insects requires application of new and more powerful pesticides
– Which leads to the emergence of a population of still more resistant insects
• The same effects arise from the use of herbicide and fungicides
• One alternative to this destructive series of events is to manage pests using a combination of natural and biological controls
• Pesticides are not only produced in laboratories; they also occur in nature
– Nicotine in tobacco and psoralens in celery are examples
– A bacterium from soil yields a pesticide often used in organic gardening
• The genetic blueprint for this bacterial pesticide has been transferred to vegetables
• Resulting in plants that grow their own pesticides in the field
• Natural pesticides are less damaging to other living things and leave less persistent residues in the environment than most human made ones
• An ideal pesticide would destroy pests in the field but vanish long before consumers ate the food
– Chemical companies are working to develop such safer pesticides
– Advances in biotechnology have reduced the need for pesticide sprays on many crops
• A possibility for consumers who want fewer pesticides in their produce and meat is to choose organic foods
– Foods grown and processed without the use of synthetic chemicals such as pesticides, herbicides, fertilisers, and preservatives and without genetic engineering or irradiation

Animal Drugs
• Growth Hormone in Meat and Milk
– Cattle producers in the U.S. commonly inject their herds with a form of growth hormone bovine somatotropin (bST)
• Promotes lean tissue growth and milk production
• Produced by genetically altered bacteria
• FDA deems the practice safe
– Does not require testing of food products for traces of the drug
• Growth hormone
– A hormone (somatotropin) that promotes growth and is produced naturally in the pituitary gland of the brain
• Bovine somatotropin (bST)
– Growth hormone of cattle,
– Can be produced for agricultural use by genetic engineering
– AKA. bovine growth hormone (bGH)
• Ranchers advocate the use of bST because injected animals develop more meat and less fat
• The hormone may also increase milk production in dairy cows up to 25%, while reducing feed requirements
– Thus farmers can earn higher profits
• Consumer groups counter that while ranchers may benefit from the use of bST, consumers do not and so its use is not justified
• The European Union and Canada ban the use of bST for milk cows
– bST stimulates the release of insulin like growth factor I (IGFI)
– Some questions have been raised about the the effects of IGFI on human health
• The FDA has concluded that IGFI levels from bST-treated cows are within the normal range of variation seen in milk from untreated cows and therefore that IGFI from this source presents no additional risk
• Antibiotics in Livestock
– Ranchers and farmers often dose livestock with antibiotics as part of a daily feeding regimen
– The drugs ward off infections that commonly afflict animals living in crowded conditions and help to promote rapid growth
• Thus, farms can produce more food at lower cost
• The USDA prohibits livestock antibiotics from entering the food supply
– Ranchers and farmers must adhere to a drug free waiting period before slaughter during which the drugs break down
– Thus, consumers face little threat of ingesting antibiotic drugs in meats, milk, and eggs
• Nevertheless, they run a substantial risk of illness from antibiotic resistant bacteria wherever animals are treated with daily antibiotics
• A limited number of antibiotic drugs exist
– When the bacteria in an animal's intestinal tract encounter daily low doses of antibiotics, the bacteria adapt, losing their sensitivity to the drugs over time
– Subsequently, such bacteria can infect consumers through food or by direct contact with ill persons
• The result is a severe infectious disease that does not yield to standard antibiotic therapy
• Arsenic in Food Animals
– Arsenic is a naturally occurring poisonous metallic element
• In trace amounts, is is believed to be an essential nutrient in some species
– In large amounts, leads to swelling of the brain, damage to the liver, etc.
• Chronic human exposure to small amounts is associated with cancers, heart disease, diabetes, birth defects and miscarriages
• Often added to insecticides and weed killers and, in tiny amounts, to certain animal drugs
• Chicken and poultry farmers often feed arsenic in tiny amounts to young flocks to control parasites that would otherwise inhibit their growth
– The USDA approves this use
• Has found that current arsenic levels in young chickens exceed expected levels by three times
• Arsenic is present in
– Fish, eggs, milk products, and other meats to a lesser extent
– Drinking water and environmental exposure may be the chief sources in some areas
• Although arsenic in chicken is higher than expected, an adult would have to eat more than 21 ounces of chicken each day to receive less than half the maximum daily arsenic level deemed safe

Environmental Contaminants
• Contaminant
– Any substance occurring in food by accident
– Any food constituent not normally present
• Chemical contaminants of concern in foods
– Heavy metals
• Arsenic
• Cadmium
• Lead
• Mercury
• Selenium

• Halogens and organic halogens
– Chlorine
– Ethylene dichloride
– Iodine
– PBB
– PCBs
– TCE
– Vinyl chloride

• Others
– Acrylamide
– Antibiotics (in animal feed)
– DES
– Dioxins
– Heat induced mutagens
– Lysinoalanine

• Harmfulness of Contaminants
– Depends in part on the extent to which it lingers in the environment or human body
• On how persistent it is
• Some contaminants are short lived because microorganisms or agents such as sunlight or oxygen can break them down
• Some contaminants linger in the body for only a short period of time because the body can rapidly excrete them or metabolise them to harmless compounds
– These contaminant present little cause for concern
• Some contaminants resist breakdown and interact with the body's systems without being metabolised or excreted
– These contaminants can pass from one species to the next and accumulate at higher concentrations in each level of the food chain
• A process called bioaccumulation
• In general, the threat remains small because the FDA monitors the presence of contamination in foods
– And issues warning when contaminated foods appear in the market
• In the event of an industrial spill or natural occurrence the hazard can suddenly become great

• Heavy metal
– Any of a number of mineral ions
– So called because they are of relatively high atomic weight
– Many heavy metals are poisonous
• Increasing levels of the heavy metal mercury expelled from industrial sites have been detected in U.S. lakes, rivers, and ocean fisheries
– Virtually all fish have at least trace amounts of mercury
• Mercury, PCBs, chlordane, dioxins, and DDT are the toxins most responsible for fish contamination
• Mercury leads the list by threefold
• When an environmental contaminant is detected in a person's blood or urine, this does not automatically mean the chemical will cause disease
– The toxicity of a chemical depends upon its dose or concentration
– Small amounts may be tolerable and of no consequence to health
– Larger amounts may be dangerous
• For some chemicals the risk of increasing blood levels are well known
– For other chemicals the health effects of varying blood levels are yet to be established
• Mercury in Seafood
– In 1953, a number of people in Minamata, Japan became ill with a disease no one had seen before
• By 1960, 121 cases had been reported, including 23 infants
• 46 died
• The survivors suffered progressive, irreversible blindness, deafness, loss of coordination, and severely impaired mental function

• Minamata disease
– Cause: manufacturing plants in the region wee discharging mercury into the waters of the bay
– Bacteria in the water were converting the mercury into a more toxic form, methyl mercury
– Fish in the bay were accumulating this poison into their bodies
• Some of the poisoned people had been eating fish from the bay every day
– Infants who contracted the disease had not eaten any fish, but their mothers had
• The mothers were spared damage during their pregnancies because the poison had been concentrating in the tissues of their unborn babies

• Today, in the U.S., the FDA and EPA warn of unacceptably high methyl mercury levels in fish and other seafood
– They advise all pregnant women, women who may become pregnant, nursing mothers, and very young children against eating fish species known to be high in methyl mercury
• The FDA and EPA suggest checking local advisories concerning fish caught by family and friends in lakes, rivers, streams, and coastal areas
– If no advice is available, one meal of locally caught fish per week is unlikely to be harmful
• But no other fish should be eaten that week
• Freshwater fish often contain PCBs and other industrial contaminants
• No one expects the tragic results of 1953 to occur again
– But lower doses of methyl mercury cause headaches, fatigue, memory loss, impaired ability to concentrate, and muscle or joint pain in adults
– In children, the threats may be greater and long lasting
• Methyl mercury is present in the environment

• In an effort to limit exposure to pollutants, some consumers choose farm raised fish
– The "farms" are really giant ocean cages
– Exposed to whatever contaminants are in the water
• Farm raised salmon, especially from Europe, recently tested high in certain industrial pollutants and pesticides that are banned from use in the U.S.
• Farm raised fish do tend to collect less methyl mercury in their flesh than wild fish do, and the levels of other harmful chemicals were far below the maximums set by the FDA

Effects of Food Processing on the Nutrients in Foods
• Many consumers rely on packaged and processed foods for convenience and speed
– So lose control over exactly what their foods contain
– Food processing involves trade offs
• Makes food safer, or gives food a longer usable lifetime, or cuts preparation time
• At the cost of some vitamin and mineral losses
• Pasteurisation
– Makes milk safe to drink
• Worth the nutrient loss
• Boxes of milk that can be kept at room temperature have been treated with ultrahigh temperature (UHT)
– A process of sterilising by exposing it short time to temperatures above those normally used in processing
• The price in terms of nutrient loss for gaining a safer food supply is probably trivial
– Sometimes processed foods even gain a nutritional edge over their unprocessed counterparts
• Such as when fat is removed from milk or other foods
• Most forms of processing aim to extend the usable life of a food
– To preserve a food, a process must prevent three kinds of events
• Microbial growth
• Oxidative changes
• Enzymatic destruction
– Occurs as active enzymes in food cells break down their internal molecular structures and cell membranes and cell walls

Extended Shelf Life
• Today, in most grocery stores, shoppers can choose foods whose shelf life has been extended through innovative packaging
– The secret to these foods' long shelf life is vacuum packaging or modified atmosphere packaging (MAP)
• Modified atmosphere packaging
– A preservation technique in which a perishable food is packaged in a gas-impermeable container from which air has been removed or to which another gas mixture has been added
• These convenient products are more expensive than comparable choices
– But, unopened, they last much longer and so save on waste
• Food manufacturers using these techniques first package foods in plastic film or other wraps that oxygen cannot penetrate
– Then, they either remove the air inside the package, creating a vacuum, or replace the air with a mixture of oxygen free gases, such as carbon dioxide and nitrogen

• Excluding oxygen
– Slows ripening of fruits and vegetables
– Reduces spoilage by mold and bacterial growth
– Prevents discolouration of cut vegetables and fruit
– Prevents spoilage of fats by rancidity
– Slows development of "off" flavours from accelerated enzyme action that breaks down flavour and aroma molecules
– Slows enzymatic breakdown of vitamins
• All foods packaged in this way must be refrigerated to keep them fresh tasting and safe
• For safety
– Consumers must read labels to distinguish between shelf stable foods and those that must be refrigerated
• As with other foods, improper storage may allow the growth of illness causing bacteria
• Consumers must also be able to identify foods too old to use

Do Canned Foods Lose Nutrients?
• Canning
– A method of preserving food by killing all microorganisms present in the food and then sealing out air
– The food, container, and lid are heated until sterile
• As the food cools, the lid makes an airtight seal, preventing contamination
• One of the more effective methods of protecting food against the growth of microbes that might otherwise spoil it
– Canned foods do have fewer nutrients
• Each small increase in temperature has a major killing effect on microbes and only a minor effect on nutrients
– In contrast, long heating times are costly in terms of nutrient losses
• Therefore, food processors employ the high temperature short time (HTST) principle for canning
• Fat soluble vitamins and most minerals are relatively stable
– Not affected much by canning
• Food scientists have paid particular attention to three vulnerable water soluble vitamins
– Thiamin
– Riboflavin
– Vitamin C
• Acid stabilises thiamin
• Heat rapidly destroys thiamin
• Foods that lose the most thiamin during canning are the low acid foods such as lima beans, corn, and meat
– Up to half, or even more, of the thiamin in these foods can be lost during canning
• Riboflavin is stable to heat
• Is sensitive to light
– Most likely to be lost from glass packed, not canned foods
• Vitamin C's special enemy is an enzyme (ascorbic acid oxidase)
– Present in fruits and vegetables
• As well as in microorganisms
– By destroying this enzyme, HTST processes such as canning actually help to preserve at least some of the product's vitamin C
• Minerals are unaffected by heat
– So they cannot be destroyed as vitamins cam be
• Both minerals and water soluble vitamins can be lost when they leach into canning or cooking water that the consumer then throws away
– Loses are closely related to the extent to which a food's tissues have been broken, cut, or chopped and to the length of time the food is in the water
• Some minerals are added when foods are canned
– Important in this respect is sodium chloride, salt, which is added for flavouring
• Many food companies have begun making low salt versions of their products
• Which may cost more because fewer low salt batches are made

Freezing
• Freezing
– A method of preserving food by lowering the food's temperature to a point that halts life processes
– Microorganisms do not die but remain dormant until the food is thawed
– Dramatically slows enzymatic reactions
• The nutrient contents of frozen foods are similar to those of fresh foods
– Losses are minimal
– The freezing process does not destroy any nutrients
– Some losses can occur in the steps before freezing
• Blanching
• Washing
• Trimming
• Grinding
• Vitamin C losses are especially likely
– Occur whenever tissues are broken and exposed to air
– Uncut fruits, especially if they are acidic, do not lose their vitamin C
• Mineral contents of frozen foods are much the same as for fresh
• Frozen foods may have a nutrient advantage over fresh
– Fresh foods are often harvested unripe
– Frozen foods are first allowed to ripen in the field
• Allows the food to develop nutrients to their fullest potential
• Foods frozen and stored under proper conditions will often contain more nutrients when served at the table than fresh fruits and vegetables that have stayed in the produce department of a store for even a day

• Frozen foods have to be kept solidly frozen at 0°F, if they are to be safe and retain their nutrients
– Vitamin C converts to its inactive form rapidly at warmer temperatures
• Food may seem frozen even at 36°F
– But much of it is actually unfrozen
• Enzyme mediated reactions can occur fast enough to completely destroy the vitamin C in only 2 months
• If foods defrost slightly but ice crystals remain
– It is probably safe to refreeze the food for later use
– At a substantial loss of nutrients, texture, and flavour
• In general, if a food is safe to eat, it is safe to refreeze
• Will lose both nutrients and appeal

Drying
• Drying
– A method of preserving food by removing sufficient water from the food to inhibit microbial growth
– Eliminates microbial spoilage
• Microbes need water to grow
– Reduces the weight and volume of foods
• Foods are mostly water
• Commercial drying does not cause major nutrient losses
– Foods dried in heated oven at home may sustain dramatic nutrient losses
– Vacuum puff drying and freeze drying
• Take place at cold temperatures
• Conserve nutrients especially well
• Sulfite additives
– Added during the drying of fruits
• Prevent browning
– Some people suffer allergic reactions when they consume sulphites
– Sulfur dioxide
• Helps preserve vitamin C
• Destroys thiamin
– Of little concern, since most dehydrated products with added sulfur dioxide are not major sources of thiamin before processing

Extrusion
• Extrusion
– A process by which the form of a food is changed
• Such as changing corn to corn chips
– Not a preservation measure
– In this process, the food is heated, ground, and pushed through various kinds of screens to yield different shapes
• Results in considerable nutrient losses
– Nutrients are usually added to compensate
• Foods this far removed from the original state are still lacking significant nutrients (notably vitamin E) and fibre

Food Additives
• Additives
– Substances that are added to foods but are normally not consumed by themselves as foods
• Compared with unregulated and untested "dietary supplements" sold directly to consumers, the 3,000 food additives in the U.S. are strictly controlled and pose little cause for concern
• Manufacturers use food additives to give foods desirable characteristics
– Colour
– Flavour
– Texture
– Stability
– Enhanced nutrient composition
– Resistance to spoilage

Regulations Governing Additives
• The FDA has the responsibility for deciding what additives shall be in foods
– To obtain permission to use a new additive in food products, a manufacturer must test the additive and satisfy the FDA that
• It is effective
• It can be detected and measured in the final food product
• It is safe for consumption
• The FDA then schedules a public hearing and invites consumers to participate
– FDA approval of an additive does not give manufacturers free license to add it to any foods
– The FDA regulation states the amounts, purposes, and foods for which the additive may be used
• No additives are permanently approved
• All are periodically reviewed
• The GRAS List
– Many substances were exempted from complying with the FDA procedure when it was first instituted because they had been used for a long time and their use entailed no known hazards
– Some 700 substances were all put on the generally recognised as safe (GRAS) list
• When substantial scientific evidence or public outcry has questioned the safety of a GRAS list additive its safety has been reevaluated
• The Margin of Safety
– Decisions about an additive's safety are governed by the important distinction between toxicity and hazard associated with substances

• Toxicity
– The ability of a substance to harm living organisms
– A general property of all substances
• Hazard
– The capacity of a substance to produce injury under conditions of its use
• All substances can be toxic at some level of consumption
– They are called hazardous only if they are toxic in the amounts normally consumed
• A food additive is supposed to have a wide margin of safety
– A zone between the concentration normally used and that at which a hazard exists
– Most additives that involve risk are allowed in foods only at levels 100 times below that at which the risk is still known to be zero
• Experiments to determine the extent of risk involve feeding test animals the substance at different concentrations throughout their lifetimes
– The additive is then permitted in foods at 1/100 the level that causes no harmful effect whatever in the animals
• In many foods, naturally occurring toxins appear at levels that bring their margins of safety close to 1/10
• Most additives used in foods offer benefits that outweigh their risks or that make the risks worth taking
– In the case of colour additives that only enhance the appearance of foods without improving their health value or safety, no amount of risk may be deemed worth taking
• Additives must not be used
– In quantities larger than those necessary to achieve the needed effects
– To disguise faulty or inferior products
– To deceive the consumer
– Where they significantly destroy nutrients
– Where their effects can be achieved by economical, sound manufacturing processes

Antimicrobial Agents
• Preservatives that protect food from the growth of microbes that can spoil the food and cause food borne illnesses
• Salt and Sugar
– The best known and most widely used antimicrobial substances
– Salt is used to preserve meat and fish
– Sugar preserves jams, jellies, ad canned and frozen fruits
– Both work by withdrawing water from the food
• Microbes cannot grow without water
• Additives such as potassium sorbate and sodium propionate are also used to extend the shelf life of
– Baked goods
– Cheese
– Beverages
– Mayonnaise
– Margarine
– Many other products

• Nitrites
– Added to meats and meat products to
• Preserve their colour
• Enhance their flavour
• Protect against bacterial growth
– In the human stomach, can be converted to nitrosamines
• Cause cancer in animals
• Reducing nitrates in consumed meats would make little difference in a person's overall exposure to nitrosamine related compounds
– The average cigarette smoker inhales 100x the nitrosamines that the average bacon eater ingests
– A beer drinker ingests 5x as much

How Do Antioxidants Protect Food?
• Food can go bad when it undergoes changes in colour and flavour caused by exposure to oxygen in the air (oxidation)
– Often these changes involve little hazard to health
• But they damage the food's appearance, taste, and nutritional quality
– Antioxidant preservatives protect food from this kind of spoilage

• Examples of common antioxidant additives
– Vitamin C
– Vitamin E (tocopherol)
– Sulphites
– BHA and BHT

• Sulphites
– Prevent oxidation in many processed foods, alcoholic beverages, and drugs
– Were used to keep raw fruits and vegetables in salad bars looking fresh
• Practice was banned after a few people experienced dangerous allergic reactions to the sulphites
• FDA now prohibits sulfite use on food meant to be eaten raw
– With the exception of grapes
– The FDA requires foods and drugs to list on their labels any sulphites that are present
– For most people, sulphites do not pose a hazard in the amounts used in products
– Sulphites can destroy a lot of thiamin in foods

• Sulfite alternatives
– Some producers use honey to clarify browned apple juice
– Agriculturists have created a hybrid apple that does not turn brown
– A combination of four GRAS additives can substitute for sulphites
• Citric acid
• Ascorbic acid
• Sodium pyrophosphate
• Calcium chloride
• BHA and BHT
– Prevent rancidity in baked goods and snack foods
• BHT
– Animals fed large amounts of BHT developed less cancer when exposed to carcinogens and lived longer than controls
• Apparently protects against cancer through an antioxidant effect similar to that of vitamin E
• To obtain this effect, a much larger amount of BHT must be present in the diet than the U.S. average
– Used experimentally at very high levels, the substance has produced cancer

Artificial colours
• Only about 10 of an original 80 synthetic colour additives are still on the GRAS list
– Among the most intensively investigated of all additives, are much better known than the natural pigments of plants
• Harmless food colourants added to the feed of farm raised salmon give their flesh an orange-red colour that consumers find appealing
• Food colourants only make foods pretty – Other additives, such as preservatives, make foods safe
– With food colours we can afford to require that their use entail no risk
• With other food additives, we must weigh the risks of using them against the risks of not using them

Artificial flavours and MSG
• Close to 2,000 artificial flavours and enhancers are approved
– Safety evaluation of flavouring agents is problematic because so many are already in use
– The flavours are strong and are used in tiny amounts unlikely to impose risks
• And they occur naturally in a wide variety of foods
• MSG
– In a few sensitive individuals produces adverse reactions known as the MSG symptom complex
• Acute, temporary, and self limiting
• Symptoms may include
– Burning sensations
– Chest and facial flushing or pain
– Throbbing headaches
• MSG symptom complex
– Plain broth with MSG seems most likely to bring on symptoms
– Carbohydrate rich meals seem to protect against symptoms
• MSG has been investigated extensively enough to be deemed safe for adults to use
– Kept out of foods for infants
• Very large doses have been shown to destroy brain cells in developing mice
• Infants have not yet developed the capacity to fully exclude such substances from their brains
– For other foods, the FDA requires that the label ingredients list itemise each additive by its full name, including MSG as monosodium glutamate

Incidental Food Additives
• Indirect or incidental additives are called additives
– Are really contaminants from some phase of production, processing, packaging, or consumer preparation
– Include tiny bits of plastic, glass, paper, tin and the like from packages and chemicals from processing, such as solvents used to decaffeinate some coffees
• Some microwave products are sold in "active packaging" that participates in cooking the food
– During the intense heat of cooking, some particles of the packaging components migrate into the food
– Regular plastic heats up less
• But particles still migrate and might not be entirely safe for consumption
• Avoid reusing disposable containers
– Margarine tubs, single use trays from frozen microwavable meals, or ordinary plastic wraps
– Microwave safe plastic wraps, waxed paper, cooking bags, parchment paper, and white microwave safe paper towels are probably safe to use
• The safest choice is to use only glass or ceramic containers or those plastic containers labeled as safe for microwaving
• Coffee filters, paper milk cartons, paper plates, and frozen food boxes can all be made of bleached paper
– Can contaminate foods with trace amounts of compounds known as dioxins
• Form during the chlorination step in making bleached paper
• Infinitesimally small amounts can migrate into foods that come into contact with bleached paper
• Such amounts do not appear to present a health risk
• Dioxins are persistent
– Leach into the environment by way of both paper mill effluent and discarded paper products in landfills
– Becoming more concentrated in land, water, and animals
• Until they build up to hazardous levels
• Incidental additives sometimes find their way into foods
– Adverse effects are rare
– These additives are well regulated

Nutrient Additives
• Include
– Enrichment nutrients added to refined grains
– Iodine added to salt
– Vitamins A and D added to dairy products
– Nutrients used to fortify breakfast cereals
• When nutrients are added to a nutrient poor food, it may appear from its label to be nutrient rich
– It is, but only in those nutrients chosen for addition
• Nutrients are also sometimes added for other purposes
– Vitamins C and E used as antioxidants
– Beta carotene as a colourant

Food Feature: Preserving Nutrients in Foods
• In general
– The more heavily processed foods are the less nutritious they become
• The Choice of Orange Juice
– Fresh juice is squeezed from the orange
• A process that extracts the fluid juice from the fibrous structures that contain it
• Each 100 calories of the fresh squeezed juice contains 111 mg of vitamin C
• When the juice is condensed by heat, frozen, and then reconstituted
– 100 calories of the reconstituted juice contain 82 mg of vitamin C
– Most people's recommended intake of vitamin C is approximately the same as the vitamin C in a single serving in any of the choices mentioned on the previous slide
• For vitamin C, the losses due to processing are not a problem
• Advantages of processing orange juice
– Fresh orange juice spoils
• Contains active enzymes that continue to degrade its compounds
• Cannot be stored indefinitely without compromising nutrient quality
– Shipping fresh juice to distant places in refrigerated trucks costs much more than shipping frozen or canned juice
• Vitamin C is readily destroyed by oxygen
– So, whatever the processing method
• Orange juice and other vitamin C-rich foods and juices should be stored properly and consumed within a week of opening
• Processing Mischief
– Processed foods are often loaded with sodium as their potassium is leached away
• Exactly the wrong effect for people with hypertension
– Processing may add sugar and fat
• Palatable, high calorie additives
• Reduce nutrient density
• Sugar and fat coated foods, such as yoghurt coated raisins, are candy
• Best Nutrient Buys
– Choose whole foods to the greatest possible extent
– Seek out among processed foods only the ones that processing has improved nutritionally
• For example, processing that removes fat
– As in fat free milk
• Commercially prepared wholegrain breads, frozen cuts of meats, bags of frozen vegetables, and canned or frozen fruit juices
– Do little disservice to nutrition
– Enable the consumer to eat a wide variety of foods
• At great savings in time and human energy
• The nutrient density of processed foods exists on a continuum
– Wholegrain bread > refined white bread > sugared doughnuts
– Milk > fruit flavoured yogurt > canned chocolate pudding
– Corn on the cob > canned creamed corn > caramel popcorn
– Oranges > orange juice . orange flavoured drink
– Baked ham > deviled ham > fried bacon
• The nutrient continuum is paralleled by another continuum
– The nutrition status of the consumer
• The closer to the farm foods you eat, the better nourished you are
• Does not mean you have to live in the fields
• Conserving Nutrients at Home
– Wise food choices are half the story of smart nutrition; skillful food preparation is the other half
• In modern commercial processing, losses of vitamins seldom exceed 25%
• Losses in the 60%-75% range occurring during food preparation at home are not unusual
• Preventing Enzymatic Destruction
– Vitamins
• Organic compounds synthesised and broken down by enzymes found in the foods that contain them
• Enzymes that break down nutrients in fruits and vegetables have a temperature optimum
– Enzymes work best at the temperatures at which the plants grow, normally about 70°F (room temperature)
• Chilling fresh produce slows down enzymatic destruction of nutrients
– To protect vitamin content, most fruits and vegetables should be
• vine ripened,
• chilled immediately after picking,
• and kept cold until use
• Protecting from Light and Air
– Besides being vulnerable to enzyme mediated spoilage, the vitamin riboflavin is light sensitive
• It can be destroyed by the ultraviolet rays of the sun or fluorescent light
– For this reason, milk is not sold (and should not be stored) in transparent glass containers
– Since grain products are also important sources of riboflavin, cooks who store them in glass jars should stow the jars in closed cupboards
• Some vitamins are acids or antioxidants and so are most stable in an acid solution away from air
– Citrus fruits, tomatoes, and many juices are acid
– As long as the skin is uncut or the can unopened, their vitamins are protected from air
• If you store a cut vegetable or fruit, cover it with an airtight wrapper; close an open carton of juice tightly and store it in the refrigerator
• Refreezing
– Labels on foods tell you "Do not refreeze."
• As food freezes, the cellular water expands into long, spiky ice crystals that puncture cell membranes and disrupt tissue structures, changing the texture and taste of the food
• There is usually no danger in eating twice frozen food although some nutrients are lost upon thawing and refreezing
• Preventing Nutrient Losses in Water
– Minerals and water soluble vitamins in fresh cut vegetables readily dissolve into the water in which they are washed, boiled, or canned
• If the water is discarded, as much as half of the vitamins and minerals in foods go down the drain with it
• Wash the intact food vigorously and briefly; don't soak it
• Cut vegetables after washing except for those such as broccoli that you have to cut to wash adequately
– For peeled vegetables, such as potatoes, add them to water that is vigorously boiling, not to cold water, to minimise the length of time the vegetables are exposed to nutrient leaching water
• Other ways to minimise cooking losses
– Steam vegetables over water rather than boiling them in it
– Stir frying vegetables in small amounts of oil conserves nutrients
– Microwave ovens are also excellent for nutrient retention
• They cook fast without requiring fats or excess liquid
• Take care when cooking in a microwave oven
– Food can become extraordinarily hot or build up steam that can scald unprotected hands or faces
• Before cooking eggs, sausages, potatoes, or any food encased in a membrane, pierce the membrane to prevent explosion of the food
– Never warm baby formula or baby food in a microwave oven
• Hot spots can form that can scald the baby
• How to tell if glass or other containers are made of microwave safe materials
– Microwave the empty container for one minute and carefully touch it
• Warm
– Unsafe for microwave
• Lukewarm
– Safe for short reheating
• Cool
– Safe for long microwave cooking times
• Preventing Nutrient Losses in Water
– Other types of cooking minimise the destruction of vitamins by avoiding high temperatures and long cooking times
• Iron destroys vitamin C by catalysing its oxidation
– Perhaps the benefit of increasing the iron content of foods by cooking in iron utensils outweighs this disadvantage

Controversy: Genetically Modified Foods: What Are The Pros and Cons?
• Organic foods is one of the fastest growing segments of the U.S. food industry
– At the same time, many U.S. farms have shifted toward growing foods altered through genetic engineering (GE)
• 80% of soybeans, 40% of corn, 70% of cotton

Genetically Modified Foods
• Issues Surrounding Organic Foods
– A farmer wishing to grow and market organic foods must receive certification by USDA inspectors
• To be sold or labeled as organic, or to bear the USDA organic seal, a food must be processed according to the procedures outlined in the following slide
• Nutrient Composition
– Little research exists to support or refute whether organic foods are nutritionally superior to conventional foods
• The nutrient differences that have been reported are so small as to be explained by the seasonal nutrient variations that normally occur in crops
– Organic candy bars, frozen soy desserts, and fried snacks are no more nutritious than ordinary treats
• Pesticide Residues
– Tests have revealed pesticide residues in about
• Three quarters of conventionally grown foods
• A quarter of organic foods
– Pesticides may persist in soils
• From previous applications
• Drift onto organic fields from nearby sprayed fields
• Contaminate organic foods during shipping or marketing
• Federal standards for pesticide residues are set far below the threshold of any known threat to human health
– The human body is well equipped to handle tiny amounts of even poisonous substances without apparent harm
• Even if organic foods were completely pesticide free, it is unlikely that this would constitute a health advantage for healthy adults
– Pesticides are more of a concern for children
• Regardless of how foods are grown, food safety concerns dictate that consumers vigorously wash all fruits and vegetables for 10 seconds under running water
– Doing so removes many harmful microbes as well as pesticide residues that may be present on conventional or organic foods
• Environmental Benefits
– In general, organic foods are grown by using the techniques of sustainable agriculture
– Vegetables and fruits are fertilised with composted animal manure or vegetable matter with no synthetic fertilisers that can run off into waterways and pollute them
• Environmental Benefits
– No synthetic pesticides or disease fighting agents are applied
• So accidental spills and overuse are not a threat
• Pests and diseases are battled by
– Rotating crops each season
– Introducing predatory insects to kill off pests
– Picking off large insects or diseased plant parts by hand
• Only pesticides from natural sources are allowed for use in organic fruits and vegetables
• Crop rotation and natural fertilisers
– minimise chemical impact on wildlife and human beings
– Are beneficial to the soil
• Curtail erosion
• Prevent contamination of drinking water from manure run off
– Which is common on commercial farms
• To produce organic eggs, dairy products, and meats
– Food producing animals are raised in spacious, low stress surroundings natural to their species with access to the outdoors
• Animals raised this way can grow large and stay healthy without growth hormones, daily antibiotics, and other drugs
• Without overcrowding, the threat to the nation's waterways from waste runoff is also greatly reduced
• Potential Health Risks
– Organic foods may not be inherently safer than conventional foods
• The application of improperly composted animal manure fertiliser may expose consumers to dangerous microbial diseases
• Unpasteurised organic juices, milk, and cheeses may constitute microbial hazards
• Organic foods contain no preservatives
– Tend to spoil faster than other foods
• Costs
– Organic foods cost more than conventional foods
• Some people are willing to pay extra for foods they believe to be superior in nutrition, benevolent to the environment, produced with respect for animals, and low in pesticides
• Some people also claim that organic fruits and vegetables taste better
• Like organic food production, genetic engineering carries its own potential set of risks and rewards
– Unlike the tried and true organic foods, GE food varieties are new to the food supply
• Genetic Engineering
– The consumer may not be able to distinguish genetically altered food from food that has not been genetically altered because the former bear no special labels
• Genetic modification techniques, particularly recombinant DNA (rDNA) technology, solve some age old agricultural problems while boosting yields and profits
• Many world governments and consumers recoil from new genetic changes in basic foods without ironclad assurances of safety
• Although genetic engineering technologies have only recently emerged from laboratories, their roots lie in genetic events taking place in nature and centuries-old selective breeding techniques that modify the genes of living things
• Natural Cross Breeding and Selective Breeding
– Before being domesticated by humans wild grains and other plants cross pollinated randomly
– Most of the resulting offspring failed to thrive
• Occasionally a new plant formed with a biological advantage that ensured its survival
– Additionally, certain wild bacteria and viruses implant genetic material in host organism cells where it may blend into the host genome and be reproduced as native genes
• Since the dawn of agriculture farmers have been changing the genetic makeup of their crop plants and farm animals through selective breeding to enhance traits desirable to human beings
– For example, today's large, full sweet cobs and high yielding corn bears little resemblance to the original wild, native corn with its sparse two or three kernels to a stalk
• Genetic Engineering Basics
– In contrast to the lengthy process of crossbreeding in nature and selective breeding in agriculture, genetic engineering can change the genetic makeup of an organism in a year or two of work
• A desirable gene from one organism can be inserted into another organism's DNA with great economy and precision
• Improving Crops for Desirable Traits
– Plants cells make likely candidates for genetic engineering because a single plant cell can often be coaxed into producing an entire new plant
– Each cell of the resulting plant contains an exact replica of the genetic information in the original cell
• If any DNA fragments are introduced into that first single cell, those fragments will be reproduced in all of the cell's offspring
– The resulting cells are clone cells
• For example, by using rDNA technology the DNA of an immature cell, known as a stem cell, from the "eye" of a potato can be altered
– A gene snipped from the DNA of a virus that attacks potato plants can be inserted into the stem cell
– This gene codes for harmless viral protein, not the infective part
• The newly created stem cell is then stimulated to grow into a transgenic organism
– The presence of the viral protein stimulates the potato plant to develop resistance and ready its defenses against an attack from the real virus in the growing field
• A gene's activity may be blocked or suppressed to reduce or eliminate the production of unwanted proteins
• For example, the first GE food produced was a long lasting tomato
– Tomatoes produce an enzyme that softens them after picking
– An antisense gene, mirror image of the native gene that codes for the "softening" enzyme, was introduced into a tomato plant
• The antisense gene blocks the production of the softener and produces otherwise normal tomatoes
• Ordinary tomatoes must be harvested at the hard, green stage to withstand handling
– A tomato with the antisense gene can be harvested and marketed at the most flavourful, nutritious redripe stage and last until long after purchase
– Such tomatoes turned out to be too expensive or troublesome to produce commercially
• Animals may be modified for the benefit of human beings
– For example, rDNA technology has been used to increase the growth rate of salmon
• The Promises of Genetic Engineering
– Supporters hail genetic engineering as nothing short of a revolutionary means of overcoming many of the planet's pressing problems, such as
• Food shortages
• Nutrient deficiencies
• Medicine shortages
• Dwindling farmland
• Environmental degradation
• Animals and plants may one day join microorganisms as manufacturers of needed pharmaceuticals products as well as extra nutrients and basic foods
• Rice, the staple food for half the world's population, may become a source of supplemental nutrition in areas where deficiencies are common
– Some GE rice produces beta carotene to fight the world's most common cause of childhood blindness: vitamin A deficiency
– Other altered rice varieties, some offering 80% more iron and zinc than ordinary rice, could relieve much suffering
• New crops can now resist insects without sprays, survive drought, or provide more complete sources of protein for people without access to animal products or adequate vegetable proteins
– Others may one day be safer for people with food allergies because scientists have successfully suppressed certain proteins that commonly cause allergy
• In areas where people cannot afford to lose a single morsel of food, plant disease can claim up to 80% of a season's sweet potatoes
– GE sweet potatoes can resist disease and save the crop
• Crops That Withstand Herbicides and Insects
– Today's first generation of genetically engineered crops fall into two main categories
• Herbicide resistant
• Insect resistant
• Farmers planting fields of crops modified to withstand potent herbicides can more easily control weeds by spraying entire fields with weed killers
– The weeds die, leaving only the desired chemical resistant crop in the field
• Insect pests are less troublesome to farmers planting crops that make plant pesticides
– Pesticides made within the tissues of the plants
– For example, a type of GE corn used for animal feed produces a pesticide that greatly reduces crop losses caused by a common corn destroying worm
• However, farmers must still spray for attacking pests not killed by the plant pesticide
• The high cost of transgenic plants and the potential that insects will become resistant to the rDNA pesticide pose problems
• Modified Microorganisms
– Genetically modified microorganisms are also currently at work
• For example, one bacterium was given the ability to make the enzyme rennin, a necessary enzyme in cheese production
• Historically, rennin was harvested from the stomachs of calves
– After a calf gene was spliced into the DNA of a bacterium the resulting transgenic colony became a factory mass producing rennin
• Another transgenic bacterial factory produces human growth hormone
– So more children with growth hormone deficiency can grow normally
• Another manufactures the hormone insulin
• Other Applications
– The techniques of genetic engineering have the power to change the most basic pattern of life in ways never before possible
• Medicine
• Forestry
• Fuel production
• Environmental protection
• Paper and plastics manufacturing
• Weapons of bioterrorism
– Treatment resistant anthrax and other disease causing organisms and biodefenses against them
• The Future of Animal Cloning
– Animals have stem cells and can be cloned
• The path to useful cloning has not been smooth
• Many cloned animals were born with serious physical imperfections and often died early
– Rats useful in medical experiments have now been successfully cloned after many years of failures
• Some cloned animals may prove useful as food
– The FDA is currently assessing the potential risks associated with consuming meats from this source
– Most likely, edible products from cloned cattle and pigs will be found safe to eat
• Issue Surrounding GE Foods
– Consumers often question whether GE foods differ substantially from other foods in their nutrient contents or safety
• Nutrient Composition
– The potential ranges for nutrients in GE foods are virtually without limit
• Except for the intentional variations, nutrients in GE foods are identical to those of comparable traditional foods
• Therefore, eating the beta carotene enriched GE rice would be the same from the body's point of view as eating plain rice and taking a beta carotene supplement
• The current manufacturing process of adding enrichment nutrients to wheat, rice, other grains, and milk products may become obsolete if rDNA plants and animals can make the extra nutrients in their tissues

• Consumers may see favorite foods such as potatoes turned into "functional foods" that sport heavy doses of disease fighting phytochemicals borrowed from less familiar foods such as flaxseed or ginger
– There is no need to worry about reduced nutrient contents of GE foods
• Consumers should stay alert to the possibility of nutrient or phytochemical overdoses
• Pesticide Residues
– Industry scientists contend that rDNA technology could virtually eliminate pesticide residues on food
– Both the nature of the pesticide and the amount present in the food are predetermined by the genetics of the plant
• Leaving no room for error or misuse by farmers
• Plant pesticides produced by GE fruits and vegetables exist in the tissues of the food
– Consumers cannot wash or peel them off before eating he food
– Nevertheless, it is unlikely that plant pesticides pose a danger to the body
• Unlike synthetic pesticides, GE plant pesticides are made of proteins that can be denatured and digested by the human body
• All pesticides, regardless of their origin, are regulated as food additives by the FDA
• One of the few pesticides approved for use on organic foods is derived from a bacterium in soil
– The extracted bacterial pesticide is a peptide chain that is lethal to insects that attack corn crops
– The GE corn receives the bacterium's gene for producing this pesticide
– The corn expresses the gene and produces the pesticide internally
• Unintended Health Effects
– Such effects may arise with any sort of genetic modification
• The relatively rare crossbreeding that occurs in nature
• Genetic engineering technology
– The results may be harmful, neutral, or beneficial to consumers
• Safety evaluations focus on each new food itself
– Rather than on the process used to create it
• Common celery provides an example of an unintended negative effect from genetic modification by selective breeding
– Over the years, celery growers chose the most attractive celery plants for reproduction
– Unbeknownst to the growers the celery stayed beautiful because it repelled pests with a natural plant pesticide whose concentrations increased with successive generations
• The pesticide causes severe skin rashes in those who handle it and are then exposed to sunlight
• An example of a positive unintended health effect of genetic engineering involves prevention of a cancer causing fungus that contaminates corn
– Scientists conferred on a corn variety the ability to produce a plant pesticide that repels attacks by common worms
– After several growing seasons, there was both less destruction by the worms and far fewer attacks by the fungus
• The worm delivered the fungus to the corn
• Intended changes to genetically modified foods are predictable
• Unintended consequences are not
– The National Academy of Sciences has established a framework for evaluating unintended effects of before they go to market
• Except for the genetic manipulation the two foods should be identical with regard to nutrients, phytochemicals, toxins, nutrient antagonists, and other constituents
• If unconventional changes are detected, each variation must be evaluated
• Even the most sophisticated chemical analysis cannot provide information about all possible health outcomes
– Foods have complex compositions, and human interactions with food magnify the scientific challenge of assessing the biological relevance of changes in a food's composition
• The degree of risk depends on factors such as the amount of the food commonly consumed and the nature of the alteration
• Environmental Effects
– Advances in rDNA technology promise bumper crops of food produced on far fewer acres of land, with less loss of water and topsoil and less use of pesticides and herbicides to end up in food and drinking water
• By one estimate, genetic engineering has already lead to an 80% reduction in insecticide use among U.S. transgenic cotton crops
• One concern is the likelihood of outcrossing
– The accidental cross pollination of plant pesticide crops with related wild weeds
– The failure to confine engineered genes may be irreversible
• No cleanup strategy for "genetic pollution" has been developed
• If a weed inherits a pest resistant trait from a neighbouring field of rDNA crops, it could gain an enormous survival advantage and crowd out other wild species
• A solution to outcrossing is the destruction of all of a GE plant's offspring by using terminator technology to alter the plan's genetic material
– This technology keeps transgenic plants from passing their genes to wild weeds
– It also makes it impossible for the world's farmers to save fertile seeds from their own harvests from year to year
• Thus, farmers are forced to buy expensive new seeds each year
• New crops may directly damage wildlife
– In the laboratory, monarch butterfly larvae die when they feed on pollen from pesticide producing corn
– In real life, wild butterflies do not seem to consume enough toxic corn pollen to be harmed
• At least in the short term
• Opposition to Biotechnology
– Some fear that by tampering with the basic blueprint of life, genetic engineering will sooner or later unleash mayhem on an unsuspecting world
– Opponents view biotechnology firms as naïve and profit driven
• Lacking the moral judgment or national laws to guide them
• Opponents point out that while rDNA technology benefits biotechnology companies and giant industrial farms, it has produced no real benefits for consumers and the risks are not defined
• Others object to rDNA technology on religious grounds
– Holding that genetic decisions are best left to nature or a higher power
• Some people envision a biotechnology run amok and used for frivolous, greedy purposes
– Such as cloning animals for amusement
– Other fear accidental doses of GE pharmaceuticals ending up in their children's breakfast bowls
– Others are alarmed at the possibility of human beings being cloned for certain traits and genetic "improvements"
• Proponents of genetic engineering respond that most of the world's people cannot afford the luxury of rejecting the potential benefits of technology
– They accuse protesters of living in an elitist world of fertile lands with abundant food
– Opponents counter that the scope of world hunger exceeds simple solutions such as increasing food supplies and that the potential for harm to those most in need outweighs any potential benefits to them
• The FDA's Position on GE Foods
– The FDA has taken the position that GE foods require no special safety testing or labeling unless they are substantially different from foods already in use
• The FDA holds the developers of the new foods responsible for testing those that differ significantly from traditional foods
• The FDA assumes that any product with an antisense gene is safe because the antisense gene prevents the synthesis of a protein and adds nothing but a tiny fragment of genetic material
• The FDA does require that any extra substances produced in the food must meet the same safety standards applied to all additives
• The case for requiring rigorous safety testing of novel constituents in GE foods is strong
– Concerns surrounding the potential for diseases, allergic reactions, and unknown hazards from unique proteins must be satisfied if GE products are to gain acceptance worldwide
• Newly altered genetic material may create unique proteins never before encountered by the human body
– Their effects should be studied and their presence regulated to ensure that people can eat them safely
• In agreement with the FDA's position is the American Dietetic Association