Chapter 25

Keeping Food Safe

Terms to Remember: Adulterated

Botulism Cross-contamination

Food infection Food intoxication Foodborne illness

Parasites Pathogenic Pesticides Residue Spores

“Wash your hands before you eat!” This standard request has been around for years, and the words still offer good advice for avoiding illness. Clean hands, however, may not offer enough protection if something isn’t right with the food you eat.

Every year in the US alone, at least 6 million people get sick from something they ate. Some estimates put the number as high as 80 million.

Nine thousand people die. These numbers are alarming. They clearly point

to the responsibility of everyone along the food supply line to make sure that food is safe.

Foodborne Illness Approximately 250 foodborne illnesses have been

identified. A foodborne illness, sometimes called food

poisoning, is an illness caused by eating food that has been contaminated in some way. Contamination can come from such things as microorganisms and their toxins, animal parasites and their eggs, viruses, and toxic chemicals.

These culprits often do their work in secret. When foodborne illness strikes, you might not notice any change in how a contaminated food looks, smells, or tastes.

Severe cases require hospitalization, but even your last bout of “stomach flu” could have been a foodborne illness.

Microorganisms and Foodborne Illness When food spoils and causes illness,

microorganisms are often to blame. These microorganisms are typically mold, yeast, and bacteria.

You may be familiar with the good work that some of these organisms do. Yeast leavens bread and ferments foods. Certain bacteria aid digestion. In contrast, some microorganisms can be

the unwelcome cause of illness.

Molds These aerobic microorganisms, which

give spoiled foods a furry look, are at home in pH ranges from 2-8.5. They prefer a moist environment and moderate temperatures ranging from 20°C, which is room temperature, to 35°C.

Some molds can grow, though more slowly, when temperatures drop to 0°C. Thus, you may find tufts of mold fuzz on bread you keep too long in the refrigerator. Because you can see and discard moldy foods, these microorganisms generally produce more waste than danger. Certain molds on improperly stored nuts, grains, and legumes, however, produce mycotoxins that can be harmful.

Yeast Yeast is a one-celled plant. Like mold, most

yeasts are aerobic, although those used in fermentation can grow without oxygen. Moisture and a pH range of 4-6.5 are essential for yeast growth.

Flourishing in an acid environment, yeast commonly forms on top of pickles and sauerkraut. It reacts with the organic acids in these foods, making the environment less acid.

Other organisms that prefer a higher pH can then continue the spoilage.

Yeast thrives at temperatures between 20°-38°C.

Growth is inhibited by low temperatures and sometimes by sugar levels of 65 percent or more.

Some yeasts prefer high concentrations of sugar, salt, or other solutes. Foods with a high sugar content—syrups, dried fruits, and concentrated fruit juices, are prime breeding ground for these yeasts.

Yeast can “ride out” harsher conditions by forming spores, microorganisms in a dormant, inactive, or resting state.

Yeast spores can survive temperatures up to 100°C.

Yeasts are probably the least threatening microorganism to food supplies.

That’s because they are routinely killed when food is processed and prepared and no risk occurs in preservation.

Bacteria By far the most threatening microorganisms in

the food supply are bacteria. Although about 20 types of bacteria can cause

foodborne illness, about eight are major causes. These single-cell organisms are found in air, soil, water, and food. They can grow both aerobically and anaerobically, depending on the type.

Some bacteria flourish even in a sealed container.

Like yeast, bacteria grow within a fairly limited pH range of 4.5-7. They need moisture and do best at temperatures ranging from 20°-50°C.

Some resistant varieties are completely destroyed only at very high temperatures, but most are killed in boiling water. When bacteria cause foodborne illness, two general results occur: Food intoxications Food infections

Food Intoxication Food intoxication is a bacterial foodborne

illness that occurs when microorganisms grow in food and produce a toxin there. The toxin causes the illness when the food is eaten.

A few examples of toxin-producing bacteria are: Clostidium Perfrigens Staphylococcus Aureus Clostidium Botulinum

Clostridium Perfringens Certain amounts of the bacteria clostridium

perfringens are in your intestinal tract all the time. Fortunately, they don’t grow there. To make you sick, they must be ingested in large numbers.

Once in the body, they form spores that release toxins in the intestinal tract. The bacteria can produce toxin only in the body. Since the toxin isn’t found in the food, these bacteria have qualities of both an intoxication and an infection.

A typical setting for C. perfringens poisoning is the holiday meal or family gathering, where foods are served, then left out as people return for extra helpings.

Meanwhile, the temperature of these foods hovers around 50°C.

Likewise, these bacteria can grow rapidly during low-temperature, long-time warming and cooking, such as slow cooker or a cafeteria heating table. They pose a problem for the food service industry, earning the nickname “the buffet germ” because they grow in conditions associated with large-scale feeding. Outbreaks of this type of food poisoning usually involve large groups of people.

C.perfringens poisoning causes stomach cramps, diarrhea, and occasional nausea. Symptoms generally appear 4-22 hours after eating and last from one to five days. This illness is rarely fatal. Most cases are never reported or are misdiagnosed as the flu or another viral infection.

Since C. perfringens occur almost everywhere, they are hard to keep out of the food supply. The problem is compounded by the bacteria’s heat-resistant spores. High and low temperatures can halt bacterial growth before in reaches dangerous levels.

Staphylococcus Aureus Better known as staph organisms, are found in

the nasal passages and on the skin. These bacteria can spread through the air in drops of moisture when you talk, sneeze, cough, or even breathe. Staph organisms usually enter food from a human or animal source.

Staph bacteria grow best in moist meat dishes and starchy foods. Sliced roast beef or ham, improperly stored, can become a staph incubator, allowing the bacteria to multiply and produce toxin.

Like C.perfringens, staph bacteria do not cause illness—their toxin does. Symptoms of food poisoning caused by staph toxin are generally felt sooner and more acutely than other types.

Diarrhea, vomiting, and stomach cramps may appear within 1-7 hours after eating and may last for 24-48 hours.

Clostridium Botulinum A very serious—and sometimes fatal—form of

food poisoning, is caused by toxin of the clostridium botulinum bacteria.

These bacteria occasionally grow in contaminated fish, but improperly home-canned foods are most often to blame.

An adult may become ill by eating spoiled food containing the botulism toxin rather than the cells themselves.

Some infants, however, get botulism from eating the C. botulinum spores.

Other bacteria that inhibit the growth of these spores aren’t well established in their systems. Honey is a common source of the spores.

Early symptoms of botulism include general weakness, blurred vision, dry mouth, difficulty swallowing or speaking, and shortness of breath.

The illness may progress to complete paralysis, respiratory failure, and even death.

Although very few cases of botulism occur each year, its life-threatening nature makes prevention of utmost importance.

Since the botulism toxin is destroyed by boiling food for 10-15 minutes, people who eat home-canned food can take this precaution before eating.

To prevent infant botulism, children under twelve months old should not be fed honey.

Food Infections Food infections are another bacterial

foodborne illness that occurs when pathogenic microoranisms enter the body along with the food eaten.

Organisms that are pathogenic are disease-carrying. If these organisms are present in food that is eaten, they can multiply in the body and cause illness.

Some examples are: Salmonella Enteritidis Escherichia Coli 0157:H7 Listeria Monocytongenes

Salmonella Enteritidis Eggs are a nutritious food. If eaten raw or

served sunny side up or soft-boiled, however, they could harbor a dose of pathogenic bacteria along with their protein and minerals.

Raw and undercooked foods—including poultry, meat products, fish, shellfish, and eggs—are favorite settings for Salmonella enteritidis. These bacteria cause salmonellosis, the most common food infection.

Milk can also be a source of Samonella. In 1985 salmonellosis struck 16,000 people in the Chicago area after they drank contaminated low-fat milk.

Since the bacteria grow at a phenomenal rate at room temperature, Salmonella infection most often occurs after eating perishable food that has been left unrefrigerated.

Problems can also arise from cross-contamination, the transfer of bacteria from one food to another food or location. If you touch a raw chicken leg carrying Salmonella and then handle raw vegetables while preparing a salad, you could transfer the bacteria to the vegetables. Once salmonellosis outbreak was linked to ice cream ingredients that were transported in a tank that had last carried unpasteurized eggs.

Generally, it takes large numbers of Salmonella to cause illness. Symptoms may appear as soon as five hours or as long as three days after the contaminated food is eaten. The time depends on how much food was eaten, the level of contamination, and the rate of digestion. Symptoms include nausea, vomiting, abdominal pain, and diarrhea. Some people experience headaches, fever drowsiness, muscle weakness, and chills.

Like other bacteria, S. enteritidis are killed by high temperatures.

Escherichia Coli 0157:H7 Ironically, one variety of Escherichia coli lives

in human intestines, where it helps digest food and metabolize vitamins.

In dramatic contrast, E. coli 0157:H7 is a hardier strain that is difficult to detect. It can also be deadly. This organism has been a major cause of illness, death and food recalls in the last decade.

E. coli 0157:H7 attacks the cells lining the intestinal wall, causing cramps and diarrhea. It can lead to the kidney disease called hemolytic uremic syndrome, which damages blood vessels, destroys platelets, and disrupts blood flow to vital organs. E. coli poisoning can also leave its victims with acute kidney failure or brain damage. E. coli can kill.

As these bacteria normally live in the intestines of cattle and other animals, poisoning usually comes from eating undercooked, contaminated beef. However, contaminated, fresh-pressed apple cider and unpasteurized milk have also caused outbreaks. In addition, E coli can be passed among people or foods that carry the bacteria.

Listeria Monocytogenes Listeria monocytogenes are often found in soil

and water. Ingesting these bacteria can cause a potentially serious illness called listeriosis. Healthy people may feel some discomfort from this disease, but those with weakened immune systems are more susceptible to its worse effects. At special risk are newborns, older adults, and pregnant women, who may experience miscarriage or stillbirth.

L. monocytogenes can lurk in the body for up to eight weeks before illness sets in. Listeriosis begins with flu-like symptoms, such as fever, chills, and sometimes nausea. If the infection spreads to the nervous system, a person may suffer from headaches, stiff neck, confusion, loss of balance, or convulsions. Listeriosis can be successfully treated with antibiotics.

L. monocytogenes can live harmlessly in the intestines of animals. From there, they spread to meat and dairy products. Soft cheese, such as Brie and Mexican-style varieties, are an especially attractive environment.

Since these bacteria are destroyed during pasteurization, look for “pasteurized” on the soft cheese labels.

The bacteria can also contaminate ready-to-eat foods after processing, either within the processing plant or on route to your plate. Ready-to-eat foods suspected in outbreaks of listeriosis include hot dogs, cold cuts, fermented or dry sausage, and other deli-style meat and poultry. These bacteria can survive at greater temperature extremes than most other organisms. Ready-to-eat foods must be heated to steaming hot to destroy the bacteria.

Animal Parasites Bacteria are not the only organisms that cause

foodborne illnesses. Parasites, organisms that grow and feed on other organisms, are another cause. Although such illnesses are rare in the US, they can occur.

Raw pork may contain a parasite called Trichinella spiralis, a tiny worm that lives in pork muscle.

If infected pork is eaten without thorough cooking to destroy the larvae ( to 77°C, 170°F), the parasite grows in the intestine and causes an illness called trichinosis. Mild cases are marked by diarrhea, fever fatigue, and muscle pain. Severe infections can fatally damage the heart and brain. Wild game is also subject to this parasite.

Viruses The Hepatitis A virus is excreted in the feces

of the infected person, who then contaminates food or water that is consumed by others. Because the infected person isn’t aware of the illness at first, the disease can spread before precautions are taken. Symptoms include fever, nausea, and abdominal discomfort, followed in several days by jaundice. Approximately 23,000 cases of Hepatitis A are reported in the US each year.

Restaurant food handlers must be very careful about sanitation because of this illness. If they contract Hepatitis A, they must take time from work to get well.

Other Causes of Foodborne Illness Chemicals. Most toxic chemicals are

unintentionally added to foods. Foods may pick up metals from processing equipment. Animals, especially fish, may ingest toxic chemicals that pollute their environment. Chemical contamination can occur in the kitchen as well. Bleaches, drain cleaners, and chemical traps for pests, if used improperly, could actually sicken the people they are meant to protect. Perhaps the biggest worry to many is pesticides, chemicals used to kill insects, animal pests, and weeds. If these products are misused or not completely removed from foods during processing, health risks could occur.

Natural Toxins. Other toxins are chemicals produced naturally by a food itself. The toxins of certain types of mushrooms can cause death within hours. Potatoes that are exposed to light may produce a chemical called solanine, which is toxic to mammals. This toxin is in the green portion under the skin and can be removed with peeling.

Government and Food Safety In 1900, the best resources for choosing safe

foods were experience, common sense, and a trustworthy butcher or produce seller. Few laws protected consumers from food that was adulterated, or made impure by the addition of improper ingredients.

Over the last century, government at local, state, and national levels has played a role in ensuring the safety of the food supply. The US government is a leader in the effort. The Wiley Food and Drug Act of 1906 was passed to enforce purity in food processing. It was replaced in 1938 by the Federal Food, Drug, and Cosmetic Act.

The responsibility for safeguarding the commercial food supply falls largely to the Food and Drug Administration (FDA) and the United States Department of Agriculture (USDA).

Food and Drug Administration To the FDA, safe means free from any hazards, and one

of the main hazards is foodborne disease. To reduce the chances of a contaminated food getting into your home, the FDA does the following:

Oversees food processing. It establishes sanitation and safety regulations and guidelines for commercial processors. FDA inspectors visit and take product samples from processing sites.

Tests for environmental contaminants. These can be toxic chemicals or metals, or industrial pollutants. In one highly publicized decision, the agency ordered the removal of swordfish from the market nationwide after unacceptable amounts of mercury were found in swordfish samples.

Sets levels of pesticides that can be used on crops. The FDA works with the USDA and the Environmental Protection Agency (EPA) to determine levels of pesticides that are effective for farmers yet safe for consumers.

Checks levels of pesticide residue in harvested foods. Residue, or residual, is the matter remaining after a chemical or physical process. Many pesticide residues are toxic to humans. The FDA does spot checks to make sure allowable limits of residues are not exceeded.

Regulates food labeling. Since the Food, Drug, and Cosmetic Act defined what a label is—”a display of written, printed, or graphic matter upon the immediate container”—the FDA has pushed to make it more accurate and informative. Sodium content on nutrition labels was mandated in 1986 to accommodate the number of people on sodium-restricted diets. In 1992, Congress passed legislation responsible for the detailed “Nutrition Facts” panel on almost all food labels.

United States Department of Agriculture The USDA is one of the most far-reaching agencies

of the federal government, overseeing food production at every stage from farm to table.

To the food producer, the USDA is a source of help and information for farming and ranching issues, from identifying pests in crops to answering questions about agricultural biotechnology.

Consumers who need to know the safest way to prepare turkey and stuffing can find that information through a USDA pamphlet, the agency’s web site, or their hot line. Research on bioengineered food is currently underway in USDA laboratories.

The food safety squad of the USDA is the Food Safety and Inspection Service (FSIS). The FSIS oversees the nation’s meat, poultry, and egg production.

Hazard Analysis Critical Control Point System One of the FSIS’s tools for preventing

foodborne hazards is the Hazard Analysis Critical Control Point System (HACCP). This process-control system was developed for NASA in preparing for space flights and has since been adopted by many industries. The FDA requires HACCP for low-acid canned food and has proposed it for the seafood industry. The USDA has similarly adopted HACCP for the meat and poultry industry.

HACCP focuses on problem prevention. Companies review their food production processes to determine the “critical control points.” These are points in the process where hazards can be prevented, controlled, or eliminated.

A HACCP program typically involves several steps.

HACCP workers identify potential hazards and the critical control points.

They can then decide how to prevent each hazard and monitor the control point.

Workers also plan corrective actions if monitoring should show that a hazard still exists.

Effective record keeping, in order to document the company’s efforts and provide a way to verify its success, is included in the HACCP system.

President’s Council on Food Safety Was established in August 1998. Its purpose is

to coordinate the resources and focus the efforts of numerous public and private groups to improve the safety of the food supply. Its goals include education and research as well as regulation and enforcement.

The council’s most prominent members are the Secretaries of Agriculture and of Health and Human Services. However, it seeks a partnership with other voices in the community who can make and carry out food safety policy. Consumer advocates, food scientists, and leaders of Native American tribes are among the many people called upon to make the venture a success.

International Agencies The US has established two organizations to

address issues related to the supply of wholesome food throughout the world.

The Food and Agricultural Organization (FAO) and the World Health Organization (WHO) identify problems and recommend improvements in how countries feed their citizens.

The FAO was formed in 1944 with the twin objectives of eliminating hunger and improving nutrition worldwide. WHO was founded four years later. WHO’s overall goal is fostering international cooperation in all health-related fields.

WHO and FAO work closely together to promote nutrition research worldwide. They produce joint reports on the nutritional state of the planet.

Governments may feel pressured to allow unsafe foods and processing methods as long as they get people fed. Some government and company officials may even try to profit by supplying adulterated foods to desperate people.

Preventing Foodborne Illness The number one cause of foodborne illness is

negligence. Someone somewhere in the food supply line, neglects some basic rules of sanitation and food handling. Following are ways to protect yourself from foodborne illness.

Practicing Cleanliness The first line of defense against the spread of

pathogenic bacteria is to keep them off the food handler.

Hand washing—a good, 20-second scrub with soap and hot water—is one of the simplest, most effective, and possibly most ignored means to do this.

Wash your hands before and after you work with food, especially when handling raw meat, poultry, or eggs.

Wash them after using the toilet, coughing, sneezing, or touching any object not involved in food handling.

Wear clean clothes, tie up long hair, and take off jewelry.

Strive for a spotless work area also. Bacteria lurk on surfaces that contact food and in food by-products. When you wipe counters with a disinfectant, clean up spills, and take out the trash, you wipe out microbe colonies.

Storing Food Safely Perishable items should be refrigerated at 4°C or

below. Closed, opaque containers protect against possible damage by light, oxygen, and microbes.

Frozen foods keep well in a freezer set at -18°C. Fresh and cooked foods intended for the freezer may need additional, airtight wrapping to prevent loss of quality from intense cold.

Nonperishable items should be kept cool and dry at room temperature. Place them in re-sealable containers to maintain freshness and quality. Avoid storing food near water pipes, an area prone to pests. Foods kept near an oven, radiator, or other heat source may be easier targets for mold and bacteria.

Store disinfectants, pesticides, and other hazardous products in a separate area, away from all food. Keep these supplies in their original containers, never in used food containers. You may never mistake white cleansing powder for Parmesan cheese, but it has happened.

Handling Food with Care To limit a food’s encounters with harmful

microorganisms, use only clean containers, utensils and serving dishes.

To prevent bacteria on raw meat and poultry from cross-contaminating other foods, use a separate cutting board for these foods.

Research suggests that plastic cutting boards may be better than wooden for cutting meats and poultry.

Wash any raw meat drippings from dishes with hot, soapy water before reusing them.

Because cutting boards can shelter bacteria, they demand special care. Cutting boards should be washed thoroughly with hot, soapy water, rinsed, and dried after each use.

Bacteria are fond of cooked foods as well. Hot foods should be kept hot—above 60°C—until served. Otherwise, they should be chilled rapidly, in the refrigerator.

Slowly cooling foods fall into that zone where bacteria grow—4° to 60°C. Refrigeration doesn’t kill bacteria; it just keeps them from multiplying.

Cooked foods cause foodborne illness more frequently than raw foods do.

Preparing Foods Properly Since bacteria are sensitive to high

temperatures, cooking a food carefully kills them.

Wiping off canned foods before opening them removes dirt.

Scrubbing unpeeled produce and peeling off outer layers of leafy greens generally reduces bacteria and residue.

Bovine Spongiform Encephalopathy (BSE) better known at “mad cow disease,” is a

chronic degenerative disease that affects the central nervous system of cattle.

There have been 180,000 verified cases of the disease worldwide, 95% of which have been in the United Kingdom.

Affected animals may lose coordination, have difficulty standing up, become nervous or aggressive, or display changes in temperament.

There is no treatment and affected cattle die.

While the cause of the disease is not fully understood, BSE is thought to be caused by something called a prion, an abnormal protein, which can cause normal prions to change and form more abnormal protein.

Whatever causes BSE, it is highly resistant to heat, ultraviolet light, ionizing radiation, and common disinfectants that would normally kill viruses or bacteria. This means that whatever causes BSE cannot be eliminated from animal tissue where it may be present.

There is no test to detect BSE in a live animal.

BSE became widespread in Great Britain because animal feed contained contaminated meat and bone meal as a protein source.

Nine years after the initial outbreak, ten cases of variant Creutzfeldt-Jakob Disease (CJD), a human disease similar to BSE, appeared in the United Kingdom. The people stricken had developed the disease from eating beef contaminated with BSE.

The US has maintained very strict controls on beef imports, as well as strict guidelines for monitoring any cattle that display symptoms that might indicate BSE.

The first case of BSE in the US did not appear until December 2003. At that time, a cow imported from Canada that was thought to be having difficulty standing because of complications from calving was slaughtered and allowed to enter the food chain.

“Downer cattle”—cows who can’t stand up—are now banned from the human food chain.

High-risk material such as the brain, spinal cord and part of the small intestine may no longer be included in human food products or dietary supplements, or in animal feed or pet food.

Look for cattle that have only been grain fed.