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Chapter 12

Food Safety and Food Technology

Sizer and Whitney, Nutrition: Concepts and Controversies, 15th Edition. © 2020 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objectives (Slide 1 of 2)

Describe microbial foodborne illnesses and core practices that can prevent them

Identify the categories of foods that most often cause foodborne illnesses

Outline technological advances aimed at reducing microbial food contamination

Describe natural toxins, pesticide residues, and contaminants in food

Learning Objectives (Slide 2 of 2)

Compare potential advantages and drawbacks of organic and conventional foods

Describe the uses and safety characteristics of some common food additives

Describe applications of food-safety practices in various settings

Summarize the advantages and disadvantages of producing food through genetic engineering

Introduction (Slide 1 of 2)

Food and Drug Administration (or F D A) areas of concern

Microbial foodborne illness

Foodborne illness: Illness transmitted to human beings through food or water

Natural toxins in foods

Residues in food

Environmental and other contaminants

Pesticide residues

Animal drugs

Nutrients in foods

With the privilege of abundance comes the responsibility to choose and handle foods wisely.

Introduction (Slide 2 of 2)

Intentional approved food additives

Genetically engineered foods

Table 12.1: Food Regulatory Agencies (Slide 1 of 2)

Each agency oversees programs and systems aimed at maintaining and improving the safety of the food supply

C D C (or Centers for Disease Control and Prevention) a branch of the U.S. Department of Health and Human Services that is responsible for, among other things, identifying, monitoring, and reporting on foodborne illnesses and outbreaks (www.cdc.gov).

E P A (or Environmental Protection Agency) a federal agency that is responsible for, among other things, regulating pesticides and establishing water quality standards (www.epa.gov).

F A O (or Food and Agriculture Organization) an international agency (part of the United Nations) that has adopted standards to regulate pesticide use, among other responsibilities (www.fao.org).

Table 12.1: Food Regulatory Agencies

Table 12.1: Food Regulatory Agencies (Slide 2 of 2)

Each agency oversees programs and systems aimed at maintaining and improving the safety of the food supply

F D A (Food and Drug Administration) the federal agency responsible for ensuring the safety and wholesomeness of all dietary supplements and foods processed and sold in interstate and international commerce except for some aspects of meat, poultry, and eggs (which are under the jurisdiction of the U S D A); setting standards for food composition and product labeling; and issuing recalls when problems arise (www.fda.gov).

U S D A (U.S. Department of Agriculture) the federal agency responsible for enforcing standards for the wholesomeness and quality of meat, poultry, and eggs produced in the United States; conducting nutrition research; and educating the public about nutrition (www.usda.gov).

W H O (World Health Organization) an international agency concerned with promoting health and eradicating disease (www.who.int).

Table 12.1: Food Regulatory Agencies

Microbes and Food Safety

Microorganisms can cause foodborne illness either by infection or by intoxication

Foodborne illnesses are caused by microbes and pathogens

Microbes: Minute organisms too small to observe without a microscope

Pathogens: Bacteria, viruses, fungi, and other microbes capable of causing illness

Can be life-threatening for certain people

Malnourished, has a compromised immune system; lives in an institution; has liver or stomach illnesses; or is pregnant, very old, or very young

How Do Microbes in Food Cause Illness in the Body? (Slide 1 of 2)

Infection agents

Salmonella or hepatitis

Intoxication

Enterotoxins: Poisons that act on mucous membranes

Neurotoxins: Poisons that act on the cells of the nervous system

Types of toxins

Most infamous types are Clostridium botulinum

Botulism which is an often fatal foodborne illness that is caused by the botulinum toxin quickly paralyzes muscles

Grows in anaerobic conditions

How Do Microbes in Food Cause Illness in the Body? (Slide 2 of 2)

Staphylococcus aureus bacterium

The most common cause of food intoxication

Shiga toxin, a protein from the E. coli bacterium

Causes the S T E C disease

Results in hemolytic-uremic syndrome

To prevent botulism from homemade flavored oils, wash and dry fresh herbs before use, and keep the oil refrigerated. Discard it after a week to 10 days.

Table 12.2: Causes, Symptoms, and Prevention of Microbial Foodborne Illnesses – Foodborne Infections (Slide 1 of 3)

Organism Name	Most Frequent Food Sources	Onset and General Symptoms	Prevention Methodsa
Campylobacter (KAM-pee-loh-BAK-ter) bacterium	Raw and undercooked poultry, unpasteurized milk, contaminated water	Onset: 2 to 5 days; Diarrhea, vomiting, abdominal cramps, fever; sometimes bloody stools; lasts 2 to 10 days.	Cook foods thoroughly; use pasteurized milk; use sanitary food-handling methods.
Clostridium (claw-STRID-ee-um) perfringens (per-FRINGE-enz) bacterium	Meats and meat products held at between 120°F and 130°F	Onset: 8 to 16 hours; Abdominal pain, diarrhea, nausea; lasts 1 to 2 days.	Use sanitary food-handling methods; use pasteurized milk; cook foods thoroughly; refrigerate foods promptly and properly.

Table 12.2: Causes, Symptoms, and Prevention of Microbial Foodborne Illnesses

Table 12.2: Causes, Symptoms, and Prevention of Microbial Foodborne Illnesses – Foodborne Infections (Slide 2 of 3)

Organism Name	Most Frequent Food Sources	Onset and General Symptoms	Prevention Methodsa
Escherichia coli; E. coli (esh-eh-REEK-ee-uh- KOH-lye) bacterium (including Shiga toxin– producing strains)a	Undercooked ground beef, unpasteurized milk and juices, raw fruit and vegetables, contaminated water, and person-to-person contact	Onset: 1 to 8 days Severe bloody diarrhea, abdominal cramps, vomiting; lasts 5 to 10 days.	Cook ground beef thoroughly; use pasteurized milk; use sanitary food-handling methods; use treated, boiled, or bottled water.
Norovirus	Person-to-person contact; raw foods, salads, sandwiches	Onset: 1 to 2 days Vomiting; lasts 1 to 2 days.	Use sanitary food-handling methods.

Table 12.2: Causes, Symptoms, and Prevention of Microbial Foodborne Illnesses

Table 12.2: Causes, Symptoms, and Prevention of Microbial Foodborne Illnesses – Foodborne Infections (Slide 3 of 3)

Organism Name	Most Frequent Food Sources	Onset and General Symptoms	Prevention Methodsa
Salmonella (sal-moh-NEL-ah) bacteria (>2,300 types)	Raw or undercooked eggs, meats, poultry, raw milk and other dairy products, shrimp, frog legs, yeast, coconut, pasta, and chocolate	Onset: 1 to 3 days Fever, vomiting, abdominal cramps, diarrhea; lasts 4 to 7 days; can be fatal.	Use sanitary food-handling methods; use pasteurized milk; cook foods thoroughly; refrigerate foods promptly and properly.
Toxoplasma (TOK-so-PLAZ-ma) gondii parasite	Raw or undercooked meat; contaminated water; raw goat’s milk; ingestion after contact with infected cat feces	Onset: 7 to 21 days Swollen glands, fever, headache, muscle pain, stiff neck.	Use sanitary food-handling methods; cook foods thoroughly.

Table 12.2: Causes, Symptoms, and Prevention of Microbial Foodborne Illnesses

Table 12.2: Causes, Symptoms, and Prevention of Microbial Foodborne Illnesses – Foodborne Intoxications (Slide 1 of 2)

Organism Name	Most Frequent Food Sources	Onset and General Symptoms	Prevention Methodsa
Clostridium (claw-STRID-ee-um) botulinum (bot-chew- LINE-um) bacterium produces botulin toxin, responsible for causing botulism	Anaerobic environment of low acidity (canned corn, peppers, green beans, soups, beets, asparagus, mushrooms, ripe olives, spinach, tuna, chicken, chicken liver, liver pâté, luncheon meats, ham, sausage, stuffed eggplant, lobster, and smoked and salted fish)	Onset: 4 to 36 hours Nervous System symptoms, including double vision, inability to swallow, speech difficulty, and progressive paralysis of the respiratory system; often fatal; leaves prolonged symptoms in survivors.	Use proper canning methods for low-acid foods; refrigerate homemade garlic and herb oils; avoid commercially prepared foods with leaky seals or with bent, bulging, or broken cans. Do not feed honey to infants.

Table 12.2: Causes, Symptoms, and Prevention of Microbial Foodborne Illnesses

Table 12.2: Causes, Symptoms, and Prevention of Microbial Foodborne Illnesses – Foodborne Intoxications (Slide 2 of 2)

Organism Name	Most Frequent Food Sources	Onset and General Symptoms	Prevention Methodsa
Staphylococcus (STAFil- oh-KOK-us) aureus bacterium produces staphylococcal toxin	Toxin produced in improperly refrigerated meats; egg, tuna, potato, and macaroni salads; cream-filled pastries	Onset: 1 to 6 hours Diarrhea, nausea, vomiting, abdominal cramps, fever; lasts 1 to 2 days.	Use sanitary food-handling methods; cook food thoroughly; refrigerate foods promptly and properly.

Note: Travelers’ diarrhea is most commonly caused by E. coli, Campylobacter jejuni, Shigella, and Salmonella.

aE. Coli O157, O145, and other Shiga toxin-producing bacteria cause toxin-mediated infections—they release toxins as their colonies grow in the body.

Table 12.2: Causes, Symptoms, and Prevention of Microbial Foodborne Illnesses

Dangerous Symptoms of Foodborne Illness (Slide 1 of 2)

Some bouts of foodborne illness may be mild and clear up on their own, but others pose serious threats. Any of the following symptoms demand medical attention

Get medical help for these symptoms

Bloody stools

Dehydration

Diarrhea of more than 3 days’ duration

Fever of longer than 24 hours’ duration

Headache with muscle stiffness and fever

Dangerous Symptoms of Foodborne Illness (Slide 2 of 2)

Numbness, muscle weakness, tingling sensations in the skin

Rapid heart rate, fainting, dizziness

Severe intestinal cramps

Warning signs of botulism—a medical emergency

Difficulty breathing

Difficulty swallowing

Double vision

Weak muscles

Food Safety from Farm to Plate (Slide 1 of 3)

Safe food supply depends on precautions taken:

On the farm or at sea

In processing plants

During transportation

At supermarkets, institutions, and restaurants

During final handling by purchasers

Safeguard to prevent outbreaks

Pasteurization: Treatment of milk, juices, or eggs with heat sufficient to kill certain pathogenic microbes. It is not a sterilization process. The products retain bacteria that cause spoilage

Food Safety from Farm to Plate (Slide 2 of 3)

The 2016 F D A Food Safety Modernization Act (or F S M A)

Hazard Analysis Critical Control Point (or H A C C P) plan

All food producers have this plan

Identification of critical control points

Food Safety from Farm to Plate (Slide 3 of 3)

Grocery safety

Batch numbering

Freshness dates

Seals, wrappers, safety “buttons”

When shopping, select frozen or refrigerated foods and fresh meats last

Eric Erbe/Christopher Pooley/United States

Department of Agriculture

Figure 12.2: Bacterial Growth.

Bacterial colonies grow quickly when a single bacterium encounters favorable conditions. For example, each oblong-shaped E. coli in this stack can reproduce every 20 minutes or so, doubling the colony size in a process that continues until conditions change (E. coli magnified 7,000 times).

Figure 12.1: From Farm to Plate: Make Food Safe

Table 12.4: Are Your Foods Expiring? (Slide 1 of 2)

Although dates on food packages do not reflect food safety, they can alert both sellers and consumers to a product’s degree of freshness

Sell by: Specifies the shelf life of the food. After this date, the food may still be safe for consumption if it has been handled and stored properly. Also called pull date

Best if used by: Specifies the last date the food will be of the highest quality. After this date, quality is expected to diminish, although the food may still be safe for consumption if it has been handled and stored properly. Also called freshness date or quality assurance date

Table 12.4: Are Your Foods Expiring? (Slide 2 of 2)

Expiration date: The last day the food should be consumed. All foods except eggs should be discarded after this date. For eggs, the expiration date refers to the last day the eggs may be sold as “fresh eggs.” For safety, purchase eggs before the expiration date, keep them in their original carton in the refrigerator, and use them within 30 daysa

Pack date: The day the food was packaged or processed. When used on packages of fresh meats, pack dates can provide a general guide to freshness

Safe Food Practices for Individuals (Slide 1 of 2)

Food provides ideal conditions for bacteria

Nutrients

Moisture

Warmth, 40°F to 140°F

Four core practices to defeat bacteria

Keep hands clean

Figure 12.3: Fight Bac!

Four ways to keep food safe. The Fight Bac! website is at www.fightbac.org.

Safe Food Practices for Individuals (Slide 2 of 2)

Keeping surfaces clean

Keep separate

Avoid cross-contamination

Cook

Chill

Thaw frozen meats or poultry in the refrigerator

Source: Photos courtesy of A. Estes Reynolds, George A. Schuler, James A. Christian, and William C. Hurst

Figure 12.4: Why Wash Your Hands?

The photo on the left shows a person’s clean-looking but unwashed hand touching a sterile, moist, nutrient-rich gel in a laboratory dish. After 24 hours in a warm incubator, the large colonies provide visible evidence of the microorganisms that were transferred from the hand to the gel.

Figure 12.6: Food-Safety Temperatures (Fahrenheit) and Household Thermometers

Cooking and cooling foods to proper temperatures reduce microbial threats. Different thermometers do different jobs. To choose the right one, pay attention to its temperature range: some have high temperature ranges intended to test the doneness of meats and other hot foods. Others have lower ranges for testing temperatures of refrigerators and freezers.

Table 12.6: Safe Food Storage Times: Refrigerator (≤40F)

For products with longer shelf lives, rotate them like restaurants do. “First-In-First-Out” means to check dates and use up older products first

1 to 2 Days	1 to 2 Weeks
Raw ground meats, breakfast or other raw sausages; raw fish or poultry; gravies	Yogurt; carrots, celery, lettuce
3 to 5 Days	2 to 4 Weeks
Raw steaks, roasts, or chops; cooked meats, poultry, vegetables, and mixed dishes; lunchmeats (packages opened); mayonnaise salads (chicken, egg, pasta, tuna); fresh vegetables (spinach, green beans, tomatoes)	Fresh eggs (in shells); lunchmeats, bacon, or hot dogs (packages unopened); dry sausages (pepperoni, hard salami); most aged and processed cheeses (Swiss, brick)
1 Week	2 Months
Hard-cooked eggs, bacon, or hot dogs (opened packages); smoked sausages or seafood; milk, cottage cheese	Mayonnaise (opened jar); most dry cheeses (Parmesan, Romano)

aFor additional information, see www.fda.gov/downloads/Food/ResourcesForYou/HealthEducators/UCM109315.pdf.

Table 12.6: Safe Food Storage Times: Refrigerator (≤40F)

aFor additional information, see www.fda.gov/downloads/Food/ResourcesForYou/HealthEducators/UCM109315.pdf.

Which Foods Are Most Likely to Cause Illness? (Slide 1 of 3)

Foods that are high in moisture and nutrients

Foods that are chopped or ground

Protein foods

Ground meats, stuffed poultry, eggs, seafood, raw milk products

Microbial dangers in sushi can’t always be detected

Raw meat can contain a prion that causes bovine spongiform encephalopathy (or B S E)

Prion: A disease agent consisting of an unusually folded protein that disrupts normal cell functioning

BSE: An often fatal illness of the nerves and brain

Figure 12.7: Food Safety Labels for Meat and Poultry

Safe handling label for raw meat and poultry

Figure 12.7: Food Safety Labels for Meat and Poultry.

Following food safety instructions for meat and poultry minimizes bacterial growth and cross-contamination.

Table 12.7: Raw Seafood Myths and Truths

Myth	Truth
If a raw seafood was consumed in the past with no ill effect, it is safe to do so today.	Each harvest bears separate risks, and seafood is increasingly contaminated.
Drinking alcoholic beverages with raw seafood will “kill the germs.”	Alcoholic beverages cannot make contaminated raw seafood safe.
Putting hot sauce on raw oysters and other raw seafood will “kill the germs.”	Hot sauce exerts no effect on microbes in seafood.

Table 12.7: Raw Seafood Myths and Truths

Figure 12.8: Hamburger Safety

A safe hamburger is cooked well done (internal temperature of 160°F) and has juices that run clear. Place it on a clean plate when it’s done.

Which Foods Are Most Likely to Cause Illness? (Slide 2 of 3)

Raw produce

Foods that grow close to the ground

Food must be scrubbed or washed to remove biofilm

Biofilm: A layer of microbes mixed with a sticky, protective coating of proteins and carbohydrates exuded by certain bacteria

Produce Safety Rule: F S M A law that regulates growing and working conditions on farms

Unpasteurized juices

Sprouts

Figure 12.9: Warning Label for Unpasteurized Juice

Unpasteurized or untreated juice must bear the following warning on its label:

WARNING: This product has not been pasteurized and therefore may contain harmful bacteria that can cause serious illness in children, the elderly, and persons with weakened immune systems.

Which Foods Are Most Likely to Cause Illness? (Slide 3 of 3)

Other foods

Imported foods such as fresh produce present a greater risk to food safety

The new F S M A rules require verification that food has been handled in keeping with the U.S. food and safety standards

Include a country of origin label

Honey contains dormant spores of Clostridium botulinum

Picnics and lunch bags

Choose foods that are safe without refrigeration, use well-aged cheeses, ensure that food can be kept chilled if required

Take-out foods and leftovers

Advances in Microbial Food Safety

Irradiation

Exposes food to controlled doses of gamma rays from cobalt 60

Does not sterilize most foods

Protects consumers

Controls foodborne illnesses

Preserves food

Controls insects on fruits

Delays sprouting and ripening

Sterilizes some products

Consumers respond negatively

Figure 12.11: Radura symbol.

This “radura” logo is the international symbol for foods treated with irradiation.

Other Technologies

Microbial testing

Automated systems have improved testing accuracy

Modified atmosphere packaging (or M A P)

Reduces oxygen

High-pressure processing (or H P P) and ultrasound

H P P compresses water to kill many kinds of pathogens

High-powered ultrasound holds promise as a sanitizer for organic salad greens

Antimicrobial wraps and films

Protects food and lends a pleasing herbal flavor to foods

Toxins, Residues, and Contaminants in Foods (Slide 1 of 3)

Many plants have natural poisons to fend off diseases, insects, and other predators

Potatoes contain solanine

Pesticides: Chemicals used to control insects, diseases, weeds, fungi, and other pests on crops and around animals

Protect crops from insect damage and increase potential yield

Toxins, Residues, and Contaminants in Foods (Slide 2 of 3)

Accumulate in the food chain and kill valuable pollinators and pests’ natural predators and pollute the water, soil, and air

Minute quantities of pesticide residues can survive processing

Infants and children are vulnerable

Immature human detoxifying system

Lower pesticide tolerance

Proportionally greater food consumption

E P A sets a reference dose

U S D A and F D A test food samples for compliance

Some insects become resistant to pesticides

Toxins, Residues, and Contaminants in Foods (Slide 3 of 3)

Organic gardens use natural pesticides

Organic gardens: Gardens grown with techniques of sustainable agriculture, such as using fertilizers made from composts and introducing predatory insects to control pests, in ways that have minimal impact on soil, water, and air quality

Consuming organic foods reduces exposure to pesticides

Organic foods: Produced without synthetic pesticides, herbicides, fertilizers, drugs, and preservatives and without genetic engineering or irradiation

Table 12.9: A Sampling of Natural Toxins

Foods	Toxic content
Herbs	Belladonna and hemlock are infamous poisonous herbs, but sassafras is also toxic; it contains the carcinogen and liver toxin safrole, which is so potent that it is banned from use in foods and beverages.
Cabbage family	Raw cabbage, turnips, mustard greens, and radishes all contain small quantities of harmful goitrogens, compounds that can interfere with thyroid hormone production and when eaten in excess, enlarge the thyroid gland.
Foods with cyanogens	Cyanogens, precursors to the deadly poison cyanide, are found in bitter varieties of cassava, a root vegetable staple for many people. Most cassava is low in cyanogens. Apricot and cherry pits present the cyanogen amygdalin, a fake cancer cure often passed off as a vitamin. aThis poison kills cancer cells but only at doses that can kill the person, too. Other fruit pits contain lower concentrations.
Seafood red tide toxin	Seafood may occasionally become contaminated with the so called red tide toxin from algae blooms. Eating the contaminated seafood can cause paralysis.

aAlso called laetrile and, erroneously, vitamin B17.

Table 12.9: A Sampling of Natural Toxins

Understanding Organic Foods (Slide 1 of 2)

Organic rules

Farmers and manufacturers must pass U S D A inspections at every step of production

Pesticide residues

Lower levels or no residue found in similar conventionally grown foods

Nutrient composition

Few differences in nutrient levels between organic and conventionally grown foods

Understanding Organic Foods (Slide 2 of 2)

Organic foods may be higher in phytochemicals

Environmental benefits

Sustainable agriculture minimizes harm

Potential pitfalls

Contamination is equally likely to occur in organic foods and conventional foods

Figure 12.3: Labels on Organic Food Products

Animal Drugs—What Are the Risks?

Antibiotic-resistant bacteria in livestock

Cause serious infection that often ends in fatality

Are a threat to humans as well

Recombinant bovine somatotropin (r b S T)

Growth hormone in meat and milk

Arsenic: A poisonous metallic element, in trace amounts, is believed to be an essential nutrient in some animal species in food

Is administered in tiny amounts to poultry

Foods such as rice and apple juice also contain small amounts of arsenic

Figure 12.14: Bioaccumulation of Toxins in the Food Chain

Plants and plankton at the bottom of the food chain become contaminated with toxic chemicals, such as methylmercury (shown as red dots)

Contaminants become more concentrated in small fish that eat the plants and plankton

Contaminants become further concentrated in larger fish that eat the small fish from the lower part of the food chain

If none of the chemicals are lost along the way, people ultimately receive all of the toxic chemicals that were present in the original plants and plankton

Figure 12.14: Bioaccumulation of Toxins in the Food Chain

Environmental Contaminants (Slide 1 of 2)

Food contaminant: Any food constituent that is not normally present

Persistence: Lingers in the environment or the human body

Bioaccumulation: Accumulation of a contaminant in the tissues of living things at higher and higher concentrations along the food chain

Toxicity: The ability of a substance to harm living organisms

Environmental Contaminants (Slide 2 of 2)

Mercury and P C Bs in seafood

Mercury in water gives rise to methylmercury, a nerve poison from aquatic bacteria

Figure 12.15: Mercury Toxicity Disease

When mercury poisons a developing fetus, the result is severe. This person has Minamata disease, the lifelong crippling of body and mind from mercury poisoning before birth.

Are Food Additives Safe? (Slide 1 of 2)

Substances that are added to foods but are not normally consumed by themselves as foods

Thousands of approved food additives in the U.S.

For F D A approval, the additive must be tested to ensure that:

It is effective

It can be detected and measured in the final food product

It is in compliance with regulations, and manufacturers can prove that the additive is safe when consumed in large amounts

Approved additives are added to the generally recognized as safe (G R A S) list

Are Food Additives Safe? (Slide 2 of 2)

Additives have a wide margin of safety

Margin of safety: A zone between the concentration normally used and that at which a hazard exists

Most additives used in foods offer benefits that may outweigh their risks or that may make the risks worth taking

Without additives, bread would quickly mold, and lunchmeat would soon spoil.

Table 12.12: Selected Food Additives and Their Functions (Slide 1 of 2)

Agent Types	Function in Foods	Examples
Antimicrobial agents (preservatives)	Prevent food spoilage by mold or bacterial growth.	Acetic acid (vinegar), benzoic acid, nitrates and nitrites, propionic acid, salt, sugar, sorbic acid.
Antioxidants (preservatives)	Prevent oxidative changes and delay rancidity of fats; prevent browning of fruit and vegetable products.	B H A, B H T, propyl gallate, sulfites, vitamin C, vitamin E.
Artificial colors	Add color to foods.	Certified food colors such as dyes from vegetables (beet juice or beta-carotene) or synthetic dyes (tartrazine and others).
Artificial flavors, flavor enhancers	Add flavors; boost natural flavors of foods.	Amyl acetate (artificial banana flavor), artificial sweeteners, M S G (monosodium glutamate), salt, spices, sugars.

Table 12.12: Selected Food Additives and Their Functions

Table 12.12: Selected Food Additives and Their Functions (Slide 2 of 2)

Agent Types	Function in Foods	Examples
Bleaching agents	Whiten foods such as flour or cheese.	Peroxides.
Chelating (KEE-late-ing) agents (preservatives)	Prevent discoloration, off flavors, and rancidity.	Citric acid, malic acid, tartaric acid (cream of tartar).
Nutrient additives	Improve nutritional value.	Vitamins and minerals.
Stabilizing and thickening agents	Maintain emulsions, foams, or suspensions or lend the desired thick consistency to foods.	Dextrins (short glucose chains), pectin, starch, or gums such as agar, carrageenan, guar, and locust bean.

Table 12.12: Selected Food Additives and Their Functions

Additives to Improve Safety and Quality

Salt and sugar

Work by withdrawing water from food

Concern with overuse

Nitrites

Preserve color and prevent rancidity and thwart bacterial growth

Safety issues: Nitrites can be converted to nitrosamines

Sulfites

Use of sulfates is strictly controlled

F D A prohibits sulfite use on food meant to be eaten raw

Salt and sugar: two long-used preservatives.

Flavoring Agents

Nonnutritive sweeteners

Sweet-tasting synthetic or natural food additives that offer sweet flavor but with negligible or no calories per serving

Acceptable daily intake (A D I)

Safety concerns about saccharin and aspartame

Monosodium glutamate (M S G)

Used widely in restaurants

M S G symptom complex: The acute, temporary, and self-limiting reactions, including burning sensations or flushing of the skin with pain and headache, experienced by sensitive people upon ingesting large doses

M S G is prohibited in baby foods

Figure 12.16: Nonnutritive Sweeteners on Food Labels

****The M S G trade name is Accent.

Figure 12.16: Nonnutritive Sweeteners on Food Labels

Fat Replacers and Artificial Fats

Provide taste, texture, and cooking with fewer or no calories

Derived from carbohydrate, protein, and fat

Artificial fat, Olestra binds fat-soluble vitamins and phytochemicals

Olestra: A nonnutritive artificial fat made from sucrose and fatty acids; also called sucrose polyester

Incidental Food Additives

Substances that are not intentionally introduced to food

Also called accidental or indirect additives

B P A: Bisphenol A, a compound that hardens plastic and a component of epoxy resin

Microwave packages are sold in active packaging that participates in cooking the food

Handling Real-Life Challenges to Food Safety

Recognizing foodborne illnesses

Take inventory of current habits

Be aware of situations that compromise food safety

Avoid eating food that is not safe

Following food-safety rules is important in all settings.

Table 12.15: More Food Safety Myths and Truths

Myths	Truths
“The five-second rule: a food that falls to the floor is safe if it is picked up within five seconds.”	Food dropped on a microbe-laden hard surface, such as a floor, becomes contaminated the moment it lands.
“If it tastes and smells okay, it’s safe to eat.”	Most microbial contamination is undetectable by human senses.
“We have always handled our food this way, so it must be safe.”	Past generations did not recognize the causes of illness.
“I sampled it a couple of hours ago and didn’t get sick, so it is safe to eat.”	Illnesses often take half a day or longer to develop.

Table 12.15: More Food Safety Myths and Truths

Controversy 12: Genetically Engineered Foods: What Are the Pros and Cons? (Slide 1 of 2)

Most people consume foods that are genetically engineered (or G E) or that are genetically modified organisms (or G M Os)

Some countries have banned G E foods

Recombinant D N A (or r D N A) technology

Based on naturally occurring genetic events

Selective breeding

Controversy 12: Genetically Engineered Foods: What Are the Pros and Cons? (Slide 2 of 2)

Accelerated selective breeding: Seedlings with the right genes are grown to maturity and reproduced to yield new breeds in a relatively short time

Some unusually colorful carrots, including the purple, light yellow, or deep red varieties now seen in some specialty grocery stores

Figure C12.1: Growth of Selected Genetically Engineered Crops, U.S. 1996–2014

Source: J. Fernandez-Cornejo and coauthors, Genetically engineered crops in the United States, Economic Research Report 162 (2014), available at www.ers.usda.gov/webdocs/publications/45179/43668_err162.pdf?v=41690.

Figure C12.1: Growth of Selected Genetically Engineered Crops, U.S. 1996–2014

Figure C12.2: Corn: A Product of Selective Breeding

Smithsonian Photo by Antonio Mortaner

Kowit Lanchu/Shutterstock.com

Figure C12.2: Corn: A Product of Selective Breeding

Biotechnology Terms (Slide 1 of 5)

Biotechnology: Science of manipulating biological systems or organisms to modify their products or components or create new products

Includes recombinant D N A technology and traditional and accelerated selective breeding techniques

Clone: Individual created asexually from a single ancestor, such as a plant grown from a single stem cell

A group of genetically identical individuals descended from a single common ancestor, such as a colony of bacteria arising from a single bacterial cell; in genetics, a replica of a segment of D N A, such as a gene, produced by genetic engineering

Table C12.1: Biotechnology Terms.

Biotechnology Terms (Slide 2 of 5)

Gene editing: Method of genetic engineering that employs CRISPR technology to alter an organism by adding, removing, or substituting molecules within a single gene’s D N A strand with great precision

CRISPR refers to a particular D N A sequence employed in the method

Genetic engineering: The direct, intentional manipulation of the genetic material of living things in order to obtain some desirable inheritable trait not present in the original organism

Also called biotechnology

Biotechnology Terms (Slide 3 of 5)

Genetically modified organism (G M O): Popular term referring to an organism produced by genetic engineering

The term genetically engineered organism (G E O) is more scientifically accurate

Outcrossing: Unintended breeding of a domestic crop with a related wild species

Plant pesticides: Substances produced within plant tissues that kill or repel attacking organisms

Biotechnology Terms (Slide 4 of 5)

Recombinant DNA (r D N A) technology: Technique of genetic modification where scientists directly manipulate the genes of living things

Includes methods of removing genes, doubling genes, introducing foreign genes, and changing gene positions to influence the growth and development of organisms

Selective breeding: A technique of genetic modification where organisms are chosen for reproduction based on their desirability for human purposes

Such as high growth rate, high food yield, or disease resistance, with the intention of retaining or enhancing these characteristics in their offspring

Biotechnology Terms (Slide 5 of 5)

Stem cell: An undifferentiated cell that can mature into any of a number of specialized cell types

A stem cell of bone marrow may mature into one of many kinds of blood cells, for example

Transgenic organism: An organism resulting from the growth of an embryonic, stem, or germ cell into which a new gene has been inserted

Recombinant D N A Technology (Slide 1 of 2)

Obtaining desired traits

Begins with D N A of a stem cell

Clone cells are created

Transgenic organism is formed

Suppressing unwanted traits by silencing the responsible genes

Human nutrition

Recombinant D N A Technology (Slide 2 of 2)

Golden Rice

Rice is an excellent vehicle for delivering vitamin A

Biofortified cassava root with minerals, vitamins, fatty acids, or promising phytochemicals

Figure C12.4: Golden Rice

Beta-carotene, the vitamin A precursor, gives Golden Rice its yellow hue.

Figure C12.15: Two Salmon Compared

These two salmon are the same age, but the G M O salmon reached market size much faster.

Figure C12.3: Comparing Selective Breeding and r D N A Technology

Selective Breeding—DNA is a strand of genes, depicted as a strand of pearls. Traditional selective breeding combines many genes from two individuals of the same species.

The Promises and Problems of r D N A Technology

Molecules from microbes

Genes of microorganisms have been altered to make pharmaceutical and industrial products

Two types of genetically engineered crops for greater crop yields

Herbicide-resistant

Insect-resistant

Plant pesticides: Pesticides made by the plant tissues themselves

Food from cloned animals

Issues Surrounding G M Os

Nutrient composition

Accidental ingestion of drugs from foods

Pesticide residues and resistance

Unintended and unpredictable health effects

Environmental effects

Loss of species

Possibility of outcrossing

Ethics and genetic engineering

Regulation of G M Os

Table C12.3: Genetic Engineering of Foods: Point, Counterpoint (Slide 1 of 7)

Arguments in Opposition to Genetic Engineering	Arguments in Support of Genetic Engineering
Ethical and moral issues. It’s immoral to “play God” by mixing genes from organisms unable to do so naturally. Religious and vegetarian groups object to genes from prohibited species occurring in their allowable foods.	Ethical and moral issues. Scientists throughout history have been persecuted and even put to death by fearful people who accuse them of playing God. Yet today, many of the world’s citizens enjoy a long and healthy life of comfort and convenience thanks to once-feared scientific advances put to practical use.
Imperfect technology. The technology is young and imperfect, and potential effects are impossible to predict. Toxins are as likely to be produced as are the desired traits.	Advanced technology. Recombinant DNA and gene editing technologies are precise and reliable. Many of the most exciting recent advances in medicine, agriculture, and technology have been made possible by the application of this technology.