understanding food-borne pathogens - career and technical

Understanding Food-borne Pathogens Supplement for CEV Video #676

Pathways for Career Success


Goal: To understand the characteristics of pathogens that cause most food-borne illness and to increase knowledge of ways to reduce the risk of acquiring a food-borne illness. Objectives:

1. to learn the characteristics of parasites, fungi, viruses and bacteria associated with food spoilage and food-borne illness

2. to learn the symptoms and related facts of the illnesses caused by

major food-borne pathogens 3. to learn food safety principles that help control illness-causing

pathogens

i


Introduction All foods contain bacteria and microbes, and these living microorganisms also can be found in the soil, on our bodies, in our bodies, on our pets—everywhere. Most of these substances are harmless and some are even beneficial, such as the microbes that help make bread and yogurt. Some cause food spoilage. Others can produce toxins that cause infection. The result is an illness, which many of us call "food-poisoning." This study guide is designed to supplement the video Understanding Food-borne Pathogens. It includes information on harmful pathogens that when ingested can cause illness. You’ll also explore ways to decrease the risk of contracting a food-borne illness through careful personal hygiene and proper handling, cooking and storage of food.

Food and Health Concerns What is Food-borne Illness? Food-borne illness is a brief sickness brought about by harmful microorganisms associated with the improper handling or preparation of food. It is estimated that food-borne illnesses cost the United States economy about five billion dollars each year and are responsible for one in every ten cases of diarrhea reported. Although normally the affected person will only feel ill for a few days, in extreme cases food-borne illness can lead to rheumatic diseases, food allergies, seizures, neurological disorders and death. The Center for Disease Control has identified approximately 250 different diseases that can be transmitted through contaminated food, with the vast majority transmitted through bacteriological pathogens. Human error is the actual "source" of the majority of food-borne illnesses. In other words, although we may say the source of an outbreak of shigella was tracked back to chicken salad, the salad was most likely contaminated when the food server used contaminated hands to scooped up chicken pieces. Additionally, even when pathogens in foods grow to dangerous levels, it is usually the fault of someone who violated a rule of food safety or sanitation. Dangers to At-Risk Populations

1

There is a special group of people for whom even a slight case of food-borne illness can be dangerous or even deadly. Those in at-risk populations include infants and children under the age of five, pregnant women, the elderly, the undernourished and those with weakened or immature immune systems. The immune systems of unborn babies, infants and young children have not yet fully developed, nor do their stomachs produce the amount of acid needed to neutralize many pathogens. Because as we age we produce less stomach acid, the elderly also fall into the at-risk category. Anyone with sub-optimal nutritional status can also be at-risk. Many people may be included in this category: anyone with a poor diet, people who are born with or acquire nutrient deficiencies, those with eating disorders, and people who are ill or recovering from illness. Another group in the at-risk population are the "immunocompromised," meaning their immune systems have been compromised, weakened or put at risk. Included in this susceptible group are people who have serious health conditions, such as drug addiction, alcoholism, cancer, liver or kidney disease, diabetes, HIV or AIDS. Added to this group are transplant recipients, because they must take immuno-suppressive drugs so their bodies don't reject the transplanted organs. Are There More Food-borne Illnesses Now? It does seem like we are hearing an increased number of media reports about food-related illness. According to the Center for Disease Control, between 400 and 500 outbreaks of food-borne illness occur each year. The Center estimates that food-borne illness will affect 6 to 80 million people and cause up to 9,000 deaths. Most cases of food poisoning or illness go unreported. The affected person spends a few days at home with diarrhea, vomiting, chills, headache and body pains, then is recovered enough to go back to work or to school. These problems are brought to our attention only when someone famous contacts a food-borne illness, when large groups of people become ill, when deaths occur, when plants fail USDA inspections or quantities of meat, strawberries or other contaminated foods are recalled. Food Industry: One reason these problems occur with more frequency is the success of the food industry. Production processes have increased the shelf-life of food dramatically. Also, food is often prepared in large quantities at different sites in the country. Within anywhere from a few hours to a few days, the products are transported from producer to distributor to wholesaler to store or restaurant. Each step in the distribution processes holds potential for risk of contamination. In addition, the speed of distribution may mean that by the time testing indicates E. coli in ground beef from a packing plant on one side of the country, the patty may be sizzling on a backyard grill on the other side of the country.

2

Also, consumer demand for food that is more convenient and produced faster and cheaper causes reciprocal problems in the food industry. Some of these problems include increased growth of untrained entry-level workers and tight schedules—situations ripe for contamination. Consumers should know that despite a few alarming breakdowns, federal, state, and local regulations and the use of food safety programs like HACCP have greatly increased the safety of our food. Improved methods of controlling bacteria, such as vacuum wrapping and irradiation, continue to be developed. Owners and workers in production, processing, transportation and food service establishments know that their reputation and livelihood can be destroyed by not providing food that is fresh, safe and wholesome. Imported Foods: Our large selection of food is the result of being able to import food from around the world. Typically, 38 percent of fruit and 12 percent of vegetables in the produce section are imported. Produce also accounts for a majority of the food-borne illnesses traced by the U.S. Federal Centers for Disease Control and Prevention—those among the top ten offenders include raspberries, strawberries, alfalfa sprouts, green onions, cantaloupes and lettuce. In addition, our grocery stores are filled with meats, candy, canned goods, mixes and packaged dinners produced completely within other countries. Due to the doubling of imported foods within the past five years, our inspection agencies are stretched to the limit. Currently, FDA inspects less than two percent of imported food shipments. We hope to never have a year like 1989, when 25,000 people became ill from salmonella on imported cantaloupes, but the potential is there. Consumers’ Eating Habits: A major reason for increased numbers of food-borne illness is our changing eating habits. Contamination can grow rapidly in these conditions: • More meals eaten away from the home, exposing us to more pathogens. • Increased consumption of convenience foods that have undergone much handling

and may not have been kept refrigerated or not cooked or reheated sufficiently. • Our foods sit out longer at room temperature: It may be hours before the meal we

picked up at the grocery store deli gets home. Take-out and home-delivery meals also involve travel time at less-than-ideal temperatures. Even when we prepare a home meal, we often grab something from the freezer and sit it on the counter to thaw quickly.

• The “dinner hour” has changed. We may leave a meal sitting out on the stove or at the table so various family members can fill their plates when their schedules allow.

Which Foods are at Risk of Bacterial Contamination? The risk of contamination rises according to several factors: • The number of times the food is handled • Temperature and time the food is held before and after preparation

3

• Acidic level of the food—a low acid level encourages bacterial growth • Processing—the less processed the food is, the more risk of contamination High Risk: unpasteurized milk and fruit/vegetable juices, uncooked eggs, raw meats and seafood, moist food maintained and served at room temperature or left unrefrigerated, foods prepared at home, home-canned foods, ice cream made with raw eggs, improperly reheated leftovers, and foods prepared where people come into contact with body products (feces, runny noses, sneezing, coughing). Medium Risk: cheese, salad bar items, unwashed fruits and vegetables, sandwiches, ground meat patties (especially fixed on an outdoor grill where uneven heat may cause patties to be undercooked in the middle), foods purchased from establishments whose main job is not serving food, such as convenience stores, and foods served from areas in which it is difficult to maintain proper holding temperatures—lunch wagons, delivery vehicles, airlines and trains. Included in the medium risk category are new food service employees still under training. *Note: all ground meat is at risk of contamination during slaughter processes. Ground beef is of special concern and in the news more often only because it is the meat most commonly consumed. Low Risk: peeled fruits, foods with high content of sugar (syrups, jellies) or acid (pickles, yogurt) or salt (cured meats, tomato paste) and foods served and kept hot or cold. In general, restaurants, caterers and other food service establishments are in the low-risk category because their personnel are specially trained in food safety areas and they must follow HACCP guidelines.

Pathogens that Cause Food-borne Illness The first defense against food-borne illness is to "understand the enemy" and know how to take steps against the illness. This section will help you do that by examining some pathogens that cause food contamination. Food-borne illness is mainly caused by four types of microorganisms: parasites, fungi, viruses, and bacteria. Fungi (mold, yeast) rarely cause more than food spoilage, and we can readily see and avoid moldy foods. Viruses cause relatively few food-borne illnesses. Due to improved livestock management, parasites are a minor source of pathogenic infection. Only one pathogen, Trichinella spiralis, will be discussed in this study guide. That leaves bacteria as the major source of food-borne illness. This section describes each type of microorganism, relates symptoms and characteristics of the illness, lists major foods or other sources most likely to carry the pathogen, and gives prevention guidelines.

Parasites

4

Trichinella spiralis Background: Trichinosis is caused by the larvae of a roundworm. The illness is passed on when the flesh of an infected animal is eaten. Illness: Illness occurs within 2-28 days. Initial symptoms include vomiting, nausea, abdominal pain, swelling around eyes. Later symptoms include muscle stiffness and fever. Sources: The larvae is sometimes found in mammals, so it can be ingested when eating food animals. Undercooked pork and cross contamination are major sources of infection. Also, wild game (especially bear and walrus) can carry the larvae in their tissues. Prevention: Trichinosis is no longer a major concern because pigs are no longer "slop fed" by hog producers, so hogs are unlikely to pick up the roundworm larvae. Cook pork and wild game meat to an internal temperature of 142º F (61ºC) to kill the organism.

Viruses Background: Two viruses account for most cases of food-related illness. The viruses thrive in water contaminated by sewage, so seafood can become infected. Foods washed with contaminated water or grown in soils irrigated with waste-water or fertilized with animal wastes also can contain the virus. However, human error causes most contamination through improper hygiene of the food server, much handling of the food that exposes the food to people who carry the virus, and poor sanitation practices where the food is being prepared. Hepatitis A Illness: Hepatitis A can cause typical food-borne illness symptoms (fever, nausea, abdominal pain, fatigue) but can also cause jaundice and serious liver damage in the victim. This slow-growing virus often doesn’t cause infection until 1 to 2 months after ingestion, making it hard to track back to its source. The illness can last for several months, can leave the recovered person weakened and susceptible to other illnesses, and liver damage may be permanent. Sources: Raw and undercooked shellfish, especially raw oysters and clams, are most often implicated in hepatitis. Other food sources include prepared salads and salad bar items. Most cases of hepatitis are caused by poor hygiene practices of food servers, because urine and feces of infected persons often serve as a vehicle for the virus. Prevention: Practice good personal hygiene and thorough hand washing, remove ill persons from service/preparation positions, use safe water supplies, obtain shellfish from certified suppliers. The virus is easily killed by normal cooking temperatures.

5

Norwalk virus Illness: The Norwalk virus is the usual cause of what is known as the “24-hour bug" or "stomach virus.” Illness occurs 24-48 hours after consumption, and the illness lasts 24-48 hours. Symptoms include nausea, vomiting, diarrhea, abdominal pain, headache and low-grade fever. Sources: Salads (particularly coleslaw) and raw shellfish are common carriers of this virus, but the virus is also found in human excretions, so unsanitary personal hygiene is usually at fault when illness occurs after eating food. Other sources that encourage bacterial growth of this virus include contaminated water, raw vegetables, eggs and icing. Prevention: Use safe water supplies, practice good personal hygiene, purchase shellfish from certified suppliers, avoid cross contamination, and cook foods thoroughly. This hardy virus can survive freezing temperatures and sanitizing solutions, but, it can be killed by normal cooking temperatures.

Fungi Mold Background: Molds cause spoilage, but rarely illness. The effects of molds include discoloration, off flavors and musty odors. Mold is a natural part of some cheeses (Brie, Bleu cheese, Camembert). Illness: Molds reproduce through spores. Although most spores are harmless to people, some cause allergic reaction and others are toxic. The toxic spores produce mycotoxins which can cause illness or pose a risk. For example, a mold called aspergillus flavus produces a potentially carcinogenic mycotoxin called aflatoxin. Sources: Individual branches grow rapidly until a colony of thousands appears as fuzzy growth on food, most commonly on bread, fruit, refrigerated meats and cheeses. Prevention: Most molds can be killed by heating the food to 140ºF (60ºC) for ten minutes. Illness-causing toxins from spores may not killed by normal cooking methods. Freezing will halt growth, but not kill mold. If mold forms on hard cheese, cut the mold and an additional ½ to 1 inch (1.27cm to 2.54cm) of cheese away from the block. Throw away soft cheese and other foods that are moldy. Yeast

6

Background: Yeasts cause some diseases in humans. However, evidence does not show that these diseases are transmitted by food or that naturally-occurring yeast in foods can cause food-borne disease. Sources: Yeasts require sugar and moisture to survive, so they are most often found in fruit juices, jellies, jams and honey. Prevention: Yeast can be killed by heating to 136º F (57ºC) for 15 minutes. On non-heatable foods such as jam, remove yeast (if only a small amount) along with a generous portion of the surrounding food. If larger amounts of yeast are present, discard the food.

Bacteria Bacteria live everywhere--air, soil, skin, even inside our mouth, nose and body. Unfortunately, even when foods reach high levels of contamination, we will probably not smell, see or taste the bacteria. That’s why it’s important if you suspect food contamination you do not “take a taste” to check for off-flavors. You may not taste anything out of the ordinary, yet ingest great quantities of toxins. Following are some of the most common bacterial pathogens that can contaminate foods, especially red meat, poultry, eggs, seafood and raw vegetables. Please note that under safe storage, cooking and holding temperatures, none of these foods are dangerous. They become dangerous when bacteria naturally present are allowed to grow to contamination level or when the foods are contaminated from other sources. Clostridium botulinum Background: C. botulinum bacteria are found nearly everywhere, especially on soil-grown vegetables. In low-acid, oxygen-free environments, the bacteria and the spores produced by the bacteria create toxins. Only a small amount of the toxin is needed to cause illness and possible death. The illness can also develop in the stomachs of people with reduced production of stomach acid, such as infants (especially 2-9 months old) and the elderly. Illness: Symptoms occur within 12 to 72 hours, but may develop as soon as 1 hour after eating. Symptoms include lack of fever, dry skin, constipation, headache, dizziness, double vision and vomiting. Because the bacteria produce a nerve toxin, later symptoms include difficulty in swallowing and speech, paralysis of muscles, respiratory failure and death. The illness lasts up to 10 days, but total recovery time can take up to a year. Mortality rate can be as high as 65%. Sources: Botulism is most often associated with improper canning, under-processed canned foods or moist, deep-dish salads. The bacteria can sometimes be smelled or seen as a milky liquid, but is not usually recognized as contamination. Low-acid foods most involved with improper home-canning are peas, green beans, mushrooms, corn, asparagus and beets. Other suspect foods include grilled onions, baked potatoes, stew, preserved meats, fermented fish products and under-processed commercially

7

canned foods. The toxin grows in the oxygen-free interior of bulk moist foods and is found naturally on many soil-grown vegetables. Honey can contain the spores, so do not give honey-sweetened foods to infants or toddlers or to the elderly. Prevention: Only a small amount of toxin needs to be ingested, so never taste food you suspect of being tainted. Don’t buy or use canned products that bulge, are dented or have rust on the seams, or jars that have broken seals. You should hear a “sucking” or “popping” sound when containers are first opened, and the liquid in canned vegetables should be clear, not milky. Scrub potatoes and other root vegetables before eating or cooking. Normal cooking temperatures will inactivate the toxins, but spores produced by the organisms are much more resistant to either heat or freezing. Important preventatives include proper sanitation, refrigeration, not buying dented cans or bulging packages from the "bargain bin" at the grocery store, scrubbing root vegetables and thorough cooking. Get medical help immediately if botulism is suspected. Clostridium perfringens Background: C. perfringens is a common microbe that grows extremely rapidly, reproducing every 8-10 minutes, and forms spores in low-oxygen, moist, warm environments. Illness: Typical symptoms of acute abdominal pains (but usually without vomiting) and diarrhea appear within 6 hours but last for less than 24 hours, and there is no fever. Sources: Foods most likely to be contaminated are red meats, poultry, seafood and cooked meats or meat casseroles that haven’t been heated or reheated sufficiently or that have been allowed to cool slowly. It is sometimes called the “cafeteria germ” because it is often associated with food services or large gatherings where foods are served warm from deep dishes. Prevention: Observe proper holding temperatures, good sanitation practices and good personal hygiene. Keep hot foods hot and cold foods cold, place leftovers in small containers and cool immediately. Replace deep-dish serving units often, and do not scrape remaining foods into the fresh container of food. Stir deep-dish contents to prevent airless pockets from forming. Campylobacter jejuni Background: C. jejuni is the most common cause of gastro-intestinal infections. It is a microaerophilic organism, which means it needs only a small amount of oxygen to grow into colonies of spiral shaped, non-sporeforming bacteria. The microbes grow in the intestine where they attack and destroy the mucus lining of the jejunum, ileum and colon surfaces. Illness: Onset of symptoms can be anywhere from within 2 days to 11 days. The illness lasts about 4 days. Symptoms include fever, dizziness, fatigue, delirium, headache, acute abdominal pain, diarrhea that lasts several weeks (sometimes with bloody stools), muscle pain and vomiting. Recovery may last up to several weeks. The jejuni organisms can be shed through feces for up to 2 months as the old lining

8

sloughs off and new lining is created, so recovered people may re-infect others through poor bathroom sanitation practices. Jejuni has been tentatively linked the pathogen to Guillain-Barre Syndrome and stomach ulcers. Sources: Jejuni bacteria are commonly found in the feces of warm-blooded animals, so can be passed on through handling animals or poor bathroom hygiene by humans. Foods most likely to encourage bacteria growth or be carriers include un-chlorinated water, unpasteurized milk, eggs, and undercooked pork and poultry—up to 80% of chicken carcasses test positive. Prevention: C. jejuni organisms are killed through proper cooking temperatures. Quick cooling and refrigeration of poultry leftovers is important. Avoid cross-contamination, especially with juices from chicken. People who work around warm-blooded animals (i.e., those employed at farms, ranches, zoos, pet stores or veterinarian clinics) or who keep pets should wash hands thoroughly after handling the animals. Food servers should be especially careful of washing their hands after using the bathroom, and childcare workers should do the same after changing diapers. Also, children who have not learned good bathroom habits should receive instruction in keeping hands out of feces and washing hands well after using the bathroom. Escherichia coli Background: E. coli is a facultative, non-sporeforming microorganism that can cause both intoxication and infection. It is found in the colon of mammals; therefore, the meat of food animals can be contaminated during the slaughter process. Ground meat is particularly susceptible to E. coli contamination because of the multi-surface nature of the product. Illness: Symptoms occur within 12 to 72 hours after consumption and can last 1 to 3 days. Intoxication symptoms include severe abdominal cramps, diarrhea, fever, nausea and vomiting. The more serious infection symptoms include hemorrhagic colitis and hemolytic uremic syndrome, characterized by bloody diarrhea and blood in urine, intense abdominal pain, vomiting, decreased or absent urine output, seizures, brain infection, blood poisoning and kidney failure. At-risk populations are especially vulnerable to E. coli. Sources: The pathogen usually infects people through improper food server hygiene, because E. coli lives in our intestines and is in our feces. The pathogen has also been found in unpasteurized cider and some other fruit juices, as well as unpasteurized dairy products, mayonnaise, and raw or undercooked beef and in ground beef and sausage. Prevention: Wash all meats and thoroughly cook, particularly ground beef patties. Wash hands before, during, and after handling meats, especially after using the bathroom or changing diapers. Be careful not to re-contaminate foods through cutting boards, knives or other utensils or through juice drippings. Adequate cooking should kill any E. coli bacteria present.

9

Listeria monocytogenes Background: Listeria is a facultative, non-sporeforming, rod-shaped bacterium. This hardy microbe can survive for long periods, likes moist conditions but can grow in environments that usually inhibit bacterial growth, and can thrive below and above normal “danger zone” temperatures. Listeria is of special concern to at risk populations because the bacteria can cause severe problems, such as blood poisoning and meningitis, and for them carries a much-higher (25%) threat of death. Pregnant women are especially at risk, because the bacteria can cause miscarriage and abortion, as well as meningitis or encephalitis in the woman or the fetus.

Illness: Within one to 21 days, most people will exhibit mild symptoms of fever, headache and vomiting, although some experience more severe symptoms, including meningitis.

Sources: Listeria bacteria are found most often in raw meats, soft cheeses and unpasteurized milk, and it has been tentatively linked to uncooked hotdogs and undercooked chicken. Game animals and fowl, as well as domestic animals, are carriers. The organisms thrive in soil, water and plant matter; therefore, the pathogen is often found on soil-grown vegetables.

Prevention: Thorough cooking kills the listeria microorganism. Keep sponges in a sanitizing solution. Avoid cross-contamination and re-contamination when cutting up raw vegetables. Cook hotdogs before eating, especially if given to children under five years of age. Salmonella Background: Salmonella is a rod-shaped, facultative, non-sporeforming bacteria commonly found in water, intestines and feces. It's the second most frequent cause of food-borne illness in the U.S., although only about 10% of the cases are reported. Certain strains of the salmonella bacteria can cause typhoid fever. Illness: Salmonellaosis lasts two to three days, and the symptoms of nausea, vomiting, abdominal pains, headache, chills and diarrhea usually appear quickly—within 12 to 14 hours. A severe strain called Salmonella choleraesusis can produce a mortality rate of up to 21 percent. Sources: Food sources include meats, poultry, eggs and foods made with them, such as sauces, custards and eggnog. Approximately 50-60% of all chicken carcasses test positive for salmonella. Animals (including humans) carry the bacteria in their intestines and feces. Prevention: Because ingestion of at least one million organisms is required to cause illness, the best prevention is washing the bacteria off meats, avoiding cross-contamination and practicing good hygiene. Adequate cooking and rapid cooling are important, although Salmonella bacteria may not always be killed by normal cooking temperatures. Eggs should be cooked until the yolk is not runny. Raw eggs should not be used in ice cream, eggnog or sauces that won’t be cooked. Utensils used to

10

beat eggs or cut up chicken should be cleaned before being used again. Wash hands after using the bathroom, changing diapers, cutting up meats or handling eggs. Shigella Background: Only a few bacteria are needed to cause illness from this very infectious, facultative pathogen. Shigellosis is also called bacillary dysentery. Illness: Symptoms consisting of diarrhea, cramps, chills, fever and nausea appear with one to seven days, although symptoms from food-related contamination may occur within seven hours. Shigellosis may last up to a week. Sources: Most likely to be contaminated with shigella are moist foods, foods not usually cooked before eating (such as raw vegetables, fruits) or that undergo much handling, such as potato, macaroni, chicken, shrimp or tuna salads. Contaminated water can spread the bacteria to food washed or being prepared, but feces on the hands of food servers and children are the most common sources of contamination. Prevention: Because humans are the prime sources of shigella contagion and because the foods most likely to become contaminated are typically served to large groups of people—at parties, cafeterias and such—personal hygiene is vital. It is also commonly spread by oral-fecal routes among young children (in nurseries, day-care centers, and elementary schools) because of their unsophisticated personal hygiene habits. Workers who must change diapers and tend to sanitation needs of dependent adults need to be especially judicious with hand washing. Staphylococcus aureus Background: Facultative, rapidly-growing, non-sporeforming staph bacteria produce toxins which cause stomach and intestinal cramps (gastroenteritis). The greatest percentage of all food-borne illnesses are caused by staph infection. These bacteria are naturally occurring in our nasal passages and on our skin, so the bacteria are usually the cause of infection in cuts and scrapes. Illness: Symptoms of food-borne illness appear within one to six hours and include nausea, vomiting, severe abdominal cramps, diarrhea, sweating, headache, fatigue and a lowered body temperature. The attack usually lasts two to three days. Although most people recover from a staph infection, their weakened immune system leaves them open to secondary infections. Sources: Foods implicated include pork, beef, turkey, chicken, eggs, dairy products (especially whipped cream and cream fillings), processed meats, macaroni salads and root vegetables (especially potato). Picnics are common sources of contamination in the summer. During the fall and winter, the bacteria become uninvited guests in food that sits out for extended periods during holiday get-togethers. The resulting illness is often blamed on "the flu." Prevention: Wash hands thoroughly after handling any suspect food. Cuts on hands must be covered or the person removed from food service until the cut heals.

11

Sneezing and coughing can contaminate food. The bacteria can be killed by normal cooking, but the toxin it produces is not killed, so the tasteless, colorless and odorless toxins can still cause illness. Prevention measures include rapid cooling, prompt refrigeration and maintaining proper holding temperatures. Other Bacterial Pathogens: A few other microbes cause a limited number of food-borne illness, mainly through fecal and sewage contamination, especially of water. Yersinia Enterocolitica causes infection within 24 to 36 hours; symptoms include diarrhea, fever, headache and severe abdominal pain like that of appendicitis. The illness can last up to two weeks and occasionally up to a year. Those afflicted also stand a greater risk of developing inflammation of the heart tissue, blood infections and arthritis. Yersinia thrives in normal refrigeration temperatures and must be pasteurized or heated to be killed. This microbe is not a common threat at present, and usually enters milk products after pasteurization. Foods implicated include water, chocolate milk, reconstituted dry milk and tofu. Vibrio vulnificus, a newly identified bacteria, causes a serious infection that is fatal in about half of the cases. Symptoms include diarrhea, fever, weakness and blood infection. The disease can be contacted through any raw or lightly cooked seafood, but especially raw oysters. Vibrio cholerae is another illness caused mainly through infected shellfish, although it can also be spread by contaminated food and water. This is the bacteria that cause cholera within two to three days after infection. Even with modern medical advances, this disease can be fatal in more than half the cases, through dehydration and cardiovascular collapse brought on from the severe diarrhea and vomiting.

Rules of Sanitation Although it is impossible to eliminate every instance of harmful microorganisms, there are many measures which can prevent or eliminate most food-borne illness. You may have noticed several recurring sources of infection in the preceding listing of causes and prevention of microbial pathogens: cross-contamination, lack of proper hand washing and letting foods sit at room temperature. We can control most of these sources. In fact, most cases of food poisoning are "caught" right in our own kitchens. The Six Rules of Sanitation The following rules of sanitation are common sense practices that should become a habit. RULE 1: Maintain acceptable personal hygiene standards. Personal hygiene includes the most critical aspect of cleanliness: frequent and thorough hand washing, including fingernails, with soap and warm water. Hand

12

washing should always follow using the rest room, blowing your nose or sneezing or coughing, handling raw foods (particularly red meat, poultry and raw vegetables), touching areas of the face, eating or drinking. Gloves provide an additional sanitary barrier between the food and handler. Fingernails should be trim and clean. Wash hands thoroughly before putting on the gloves. Restrain long hair so it doesn't come into contact with food. Servers should not touch their hair, scratch their nose, rub their eyes or make other personal contact when preparing or serving food and drink. Do not chew gum, eat or use tobacco products in areas of food preparation. Do not taste food with a utensil that will again be used in the preparation of food. RULE 2: Prevent those who are ill and those who have open cuts from preparing and handling food products. Microorganisms responsible for an individual's illness can easily be transmitted to food and cause illness to others. Open cuts pose a threat not only to the diners but also to the individual preparing the food; microorganisms from food can more easily penetrate the body through a wound and cause infection, and our wounds contain staph germs we could pass on to others. RULE 3: Wash raw food products thoroughly. Raw foods, especially red meat and poultry, can harbor harmful bacteria. Thorough washing with water and rubbing the outside with your fingers will remove many microorganisms from the food's surface. It is easy and healthy to strip the skin off chicken before washing it. Wash packaged fruits and vegetables, as well as those purchased loose in a bin. RULE 4: Store foods at correct temperatures. Frozen foods should be stored at 0° Fahrenheit or below (-18ºC). A refrigerator's temperature should be kept at 40°F (4ºC) or slightly lower. Microorganisms grow best between 40°F and 140°F (4ºC and 60ºC). This one-hundred-degree range is called the Temperature Danger Zone. Make every effort to keep foods out of the Temperature Danger Zone; this will not only prevent bacteria growth, but reduce food spoilage as well. Remember: Bacteria are not destroyed by temperatures less than 145°F (63ºC). Cold foods should be held at less than 40°F (4ºC) and hot foods at 145°F (63ºC) or above. RULE 5: Keep the equipment, utensils and work area clean.

13

Properly wash utensils you use during food preparation or cooking. Do not wipe dry; instead, let the utensils dry in the air. Wiping with cloth can re-contaminate equipment and utensils. Equipment that is stationary or too large for sinks should be scraped and pre-rinsed, washed with 120°F (49ºC) water, wiped with a suitable sanitizing solution, and allowed to air dry. Wood cutting boards and wooden-handled utensils can trap and harbor potentially hazardous germs; clean and then sanitize them after use. Better yet, replace them with easier-to-clean materials. RULE 6: If in doubt, throw it out. Throw out perishable food that has been sitting for more than two hours at room temperature or more than one hour at 90° (32ºC) or higher. Do not use food items which have passed their expiration date. If a can or bag is punctured, torn or bulges (not from air packing as for fragile snacks like potato chips), do not use the product. Examine perishable food items for any sign of bacteria or for mold growth. If a food product smells "funny," spoilage has probably occurred. If a canned item, especially a low-acid vegetable like peas or green beans, looks milky or smells wrong, there may be deadly C. botulism present. DON’T taste it. Throw it out!

14

Understanding Food-borne Pathogens Student Activities for CEV Video #676

1. Do You See What I See? Divide students into groups. Have each group plan a

skit that reveals several food safety and/or sanitation errors. While one group performs the skit, the other groups record the errors. After the skit, see which group found the most errors. Examples might include: preparing a snack, at a picnic, attending a party, packing a lunch, late-night studies and snacks, a take out meal or delivery and cleaning out a refrigerator.

2. What's the Diagnosis? Have a student "patient" give symptoms to another

student "doctor." As the drama unfolds, groups of student "interns" confer with each other and try to determine the name of the pathogen causing the problem.

3. Telephone Doctor: Similar to above, but students work in pairs. One "patient" calls

up the "doctor" and describes his or her symptoms, one at a time, trying to stump the doctor as long as possible. The "doctor" tries to guess the pathogen or illness in the least number of clues.

4. Discard! Students make cards, each with the name of a different pathogen. As the

teacher or another student reads descriptions, students remove cards of pathogens that don't fit the description, until only a few or one possibility remains.

5. Research Topics: Allow students to research food-borne illness statistics of

various cities for the most current time period available (teachers may want to divide groups into time zones, so groups will not duplicate cities chosen and in case students have trouble locating data for several cities). The groups can then report their findings.

Data uncovered might include number of cases listed under each pathogen,

pathogens not mentioned in the video, conclusions the group was able to draw and evidence to back up the conclusion, and age/group comparisons among the cities.

1

6. How Are We Doing? Have the class work together to create a brief, generic checklist for using in various circumstances, including a space to record observed weak areas or abuses, a point system and a grading scale. Duplicate the checklists so each student can have several. Then have individual students, as they have opportunity, secretly use the checklist and report back to the class within a specific time frame, such as one week.

Areas students might observe include a fine restaurant, fast food restaurant, deli,

grocery store deli, grocery produce aisle, their own kitchens, party, convenience store deli, cafeteria, day care center and so on. Remind students to mark down the name and type of the establishment, date, time of day, and to be specific in errors noted. Also remind them that the object of the task is to evaluate how well their community observes good food safety and sanitation practices, not to make an object lesson of an establishment or to become a crusader for perceived abuses.

2

Understanding Food-borne Pathogens Discussion Questions for CEV Video #676

1. Why are bacteria of more concern to health specialists than either fungi, parasites

or viruses? 2. Why do the elderly and transplant recipients need to be more cautious about

contracting a food-borne illness? What other groups are often included in at-risk populations?

3. How can food servers make sure they don't pass illness-causing bacteria on to

their guests? 4. If you attended a catered reception where food was present during the entire

affair, what food safety features would you look for? 5. Name three types of food that were often mentioned as possible sources of

contamination, and list safety or sanitation guidelines you could follow to reduce risk of food-borne illness.

Understanding Food-borne Pathogens

1

Supplement for CEV Video #676 In the blank, write the letter of the pathogen that best matches the description.

a. Trichinella spiralis f. Clostridiuim perfringens k. Shigella b. Staphylococcus aureus g. Clostridiuim botulinim l. mold c. Escherichia coli h. Campylobacter jejuni m. yeast d. Listeria monocytogenes i. Norwalk virus e. Hepatitis A j. Salmonella

___1. Look for discoloration, fuzzy-looking growth and musty odor. ___2. Also called the "cafeteria germ." Symptoms appear quickly and leave quickly,

and there is usually no fever. Prevention includes stirring food in deep dish serving units.

___3. Found in the colon of mammals, including humans. Most outbreaks are due to

contamination of ground beef during slaughter or poor hygiene from food server.

___4. Only a few of these bacteria are needed to cause illness. Suspect foods

include moist foods that undergo a lot of handling, such as chicken salad. ___5. Pork is rarely contaminated now, but hunters should thoroughly cook their wild

game. ___6. Beware of cans with dents and packages that bulge. The bacteria live naturally

on low-acid, soil-grown vegetables. The illness comes on quickly and can be deadly.

___7. The bacteria are carried on potato skin and our own skin. Cooking kills the

bacteria but not the toxin. The illness comes on quickly and is often mistaken for the flu.

___8. The illness, probably brought to you by your food server, may not appear until

a month or two after eating undercooked or raw shellfish. It can cause liver damage.

___9. This illness can be painful, because the pathogen destroys the mucus lining of

the jejunum. Up to 80% of chicken carcasses carry the bacteria. ___10. It can live in the Danger Zone and is especially dangerous for pregnant women. EXTRA CREDIT: Match the pathogen (mentioned only in the study guide) to its description. n. Yersinia enterocolitica o. Vibrio vulnificus p. Vibrio cholerae

2

___1. Eating raw oysters contaminated with this bacteria can kill nearly half of the

victims. ___2. This bacteria can cause cholera, with a death rate of more than 50%. ___3. Thrives in refrigeration temperatures and can cause heart inflammation.

3

Understanding Food-borne Pathogens Video Quiz I & II

Short Answer

1. In general, who is at risk of contracting a food-borne illness?

2. Name the four types of microorganisms of concern to food service personnel. Multiple Choice ___ 3. Trichinella spiralis is a roundworm which may be found in

a. seafood b. poultry c. mammals d. insects

___ 4. The disease caused by Trichinella spiralis is known as

a. the flu b. trichinosis c. trichinitis d. salmonellosis

___ 5. To kill Trichinella spiralis, food must be cooked to at least

a. 130° F (54ºC) b. 148° F (64ºC) c. 112° F (44ºC) d. 142° F (61ºC)

___ 6. Which of these is not a common symptom of Trichinella spiralis infection?

a. vomiting

4

b. abdominal pain c. nausea d. severe headache

Discussion

7. Briefly discuss why Trichinella spiralis has been largely eradicated in the United States.

5

Understanding Food-borne Pathogens Video Quiz III

True or False ___ 1. Symptoms of Hepatitis A infection appear almost immediately. ___ 2. Contaminated water supplies are a possible source of viral food-borne ___ 3. Humans are the only known host of the Norwalk virus. ___ 4. The Norwalk virus cannot withstand freezing or chlorine sanitizing ___ 5. Hepatitis A and Norwalk viruses can easily survive normal cooking

temperatures. Short Answer

6. Symptoms of Hepatitis A infection include inflammation of what organ?

7. Name two common symptoms of Hepatitis A and Norwalk virus infections.

6

Understanding Food-borne Pathogens Video Quiz IV

True or False ___ 1. Individual mold plants can easily be seen with the naked eye. ___ 2. Molds form spores as a means of reproduction. ___ 3. Yeasts and molds are a major cause of food-borne illness. ___ 4. Molds are easily killed by freezing. ___ 5. Yeasts and molds (but not necessarily their toxins) can be killed by heating to

140° F (60ºC) for 15 minutes. Short Answer

6. Name two cheeses in which molds are desirable.

7. What two nutrients do yeast require to survive?

8. Name two foods in which yeasts are most likely to cause spoilage.

Understanding Food-borne Pathogens

7

Video Quiz V Multiple Choice ___ 1. Which of the following is not a common symptom of most bacterial food-borne

illnesses? a. nausea b. vomiting c. headache d. cough

___ 2. Which of the following bacteria does not produce a toxin?

a. Salmonella b. Staphylococcus aureus c. C. botulinum d. E. coli

___ 3. Which of the following is a spore-forming bacteria?

a. E. coli b. Salmonella c. C. perfringens d. C. jejuni

___ 4. Which of the following bacteria is not classified as facultative?

a. Staph b. C. botulinum c. L. monocytogenes d. E. coli

Short Answer

5. Which bacteria is associated with improper canning?

6. Which bacteria is a major concern to pregnant women?

8

7. Which bacteria is the most infectious, requiring only a few organisms to cause illness?

8. Which bacteria causes the largest percentage of bacterial food-borne illness?

9. Which bacteria has the highest mortality rate?

10. Which bacteria is classified as anaerobic?

9

Understanding Food-borne Pathogens Video Quiz VI

True or False ___ 1. E. coli bacteria are found only in the feces of cattle. ___ 2. Staph bacteria can be found in cut and skin lesions. ___ 3. Bacteria found on and in our bodies are responsible for most food-related

illnesses. ___ 4. Keep hot foods hot and cold foods cold. Discussion 5. Briefly discuss the six steps that help reduce the risk of food-borne illness. Scenarios The videotape contains three scenarios that show typical food preparation scenes. For each scene, write the problem that may cause food-borne illness and the solution. Scenario # 1: Cook cuts chicken into pieces, then takes the same knife and begins cutting the fat from a piece of red meat. Scenario # 2: Food service employee uses the bathroom (you can hear a toilet flushing), checks his hair in the mirror, then leaves. Scenario # 3: Cook is shown cutting up potatoes. Note: students should be able to view the scenario and determine the potential hazards present.)

Understanding Food-borne Pathogens 10

Final Quiz Short Answer 1. What class of animals is the most common host of Trichinella spiralis? 2. Which virus usually causes the common stomach flu or "24-hr. bug''? 3. Name the two types of fungi associated with food-borne illness. 4. Which group of food-borne pathogens causes host cases of food-borne illness? 5. Which bacteria are known for rapid multiplication? 6. Which bacteria are the most deadly? 7. Which bacteria can cause miscarriage or abortion in pregnant women? 8. Why are bacteria that produce toxins especially dangerous? 9. Which two bacteria are commonly found on and in our bodies? 10. What personal hygiene practice is most important in preventing food-borne illness?

11

Understanding Food-borne Pathogens Answer Key-Discussion Questions for CEV Video #676

1. Why are bacteria of more concern to health specialists than either fungi, parasites or

viruses? Fungi may cause food spoilage, but does not often caused food-borne illness. Few parasites are food-related problems, and trichinosis has been largely eradicated so is not a major threat. There are only two viruses--Hepatitis A and Norwalk virus—that are of any major concern to food-borne illness. Of the more than 250 food-borne diseases that the Center for Disease Control identifies, the major threat by far is from bacteriological pathogens.

2. Why do the elderly and transplant recipients need to be more cautious about

contracting a food-borne illness? What other groups are often included in at-risk populations?

The elderly have reduced production of stomach acid, our principal defense against pathogens. Transplant recipients take drugs that reduce their immune system responses so their bodies don't reject the transplanted organ; in that weakened state they are at risk of contracting a food-borne illness. There are other groups of people considered at greater risk because the pathogens may be stronger than their immune defenses can withstand: children below the age of five, pregnant women, the chronically ill or those recovering from an illness, the malnourished and those born without or who later develop a nutrient or immune deficiency.

3. How can food servers or those who prepare meals at home make sure they don't

transmit illness-causing bacteria to their guests? Food servers should restrain their hair and not push back their hair or touch their faces with their hands. They should wear gloves when serving food. They should make sure cuts are covered. They should take care not to cough or sneeze when serving. After using the bathroom, they should wash their hands thoroughly with soap and warm water, and they should rewash their hands often during their shift. Employees who are ill should not prepare or serve food. They should make sure their fingers or hands do not touch the food, utensils or glassware. If part of their duties includes bussing tables, they should use sponges or cloths kept in sanitizing solutions and changed out often.

4. If you attended a catered reception where food was present during the entire affair,

what food safety features would you look for?

1

Look for hot food kept hot and cold food kept cold. Serving dishes or trays should be shallow, food stirred often and replaced when it runs low (new food should not just added to older food in the container). Food servers should have hair restrained, wear gloves when serving and have access to washing facilities.

5. Name three types of food that were often mentioned as possible sources of

contamination, and list safety or sanitation guidelines you could follow to reduce risk of food-borne illness.

Meat: wash surfaces, cook thoroughly (esp. ground meat and pork), avoid cross-contamination. Seafood: purchase from certified waters, cook thoroughly, stir bulk salads and casseroles. Dairy products and juice drinks: make sure they are pasteurized, kept cool. Eggs and chicken: don't use raw eggs in foods, wash chicken and cook thoroughly. Vegetables: scrub raw vegetables before eating or using in food. Canned foods: don't use cans with dents, leaks or bulges or jars with leaking seals. Convenience foods: make sure they are properly refrigerated, cooked or reheated.

2

Understanding Food-borne Pathogens Answer Key for CEV Video #676

In the blank, write the letter of the pathogen that best matches the description.

a. Trichinella spiralis f. Clostridiuim perfringens k. Shigella b. Staphylococcus aureus g. Clostridiuim botulinim l. mold c. Escherichia coli h. Campylobacter jejuni m. yeast d. Listeria monocytogenes i. Norwalk virus e. Hepatitis A j. Salmonella

l 1. Look for discoloration, fuzzy-looking growth and musty odor. f 2. Also called the "cafeteria germ." Symptoms appear quickly and leave quickly,

and there is usually no fever. Prevention includes stirring food in deep dish serving units.

c 3. Found in the colon of mammals, including humans. Most outbreaks are due to

contamination of ground beef during slaughter or poor hygiene from the food server.

k 4. Only a few of these bacteria are needed to cause illness. Suspect foods include

moist foods that undergo a lot of handling, such as chicken salad. a 5. Pork is rarely contaminated now, but hunters should thoroughly cook their wild

game. g 6. Beware of cans with dents and packages that bulge. The bacteria live naturally

on low-acid, soil-grown vegetables. The illness comes on quickly and can be deadly

b 7. The bacteria are carried on potato skin and our own skin. Cooking kills the

bacteria but not the toxin. The illness comes on quickly and is often mistaken for the flu.

e 8. The illness, probably brought to you by your food server, may not appear until a

month or two after eating undercooked or raw shellfish. It can cause liver damage.

h 9. This illness can be painful, because the pathogen destroys the mucus lining of

the jejunum. Up to 80% of chicken carcasses carry the bacteria. d 10. It can live in the Danger Zone and is especially dangerous for pregnant women. EXTRA CREDIT: Match the pathogen (mentioned only in the study guide) to its description. n. Yersinia enterocolitica o. Vibrio vulnificus p. Vibrio cholerae

3

o 1. Eating raw oysters contaminated with this bacteria may cause serious blood

infections. p 2. This bacteria can cause cholera, with a death rate of more than 50%. n 3. This pathogen thrives in refrigeration temperatures and can cause heart

inflammation.

4


Short Answer

1. In general, who is at risk of contracting a food-borne illness? everyone

2. Name the four types of microorganisms of concern to food service personnel. parasites, viruses, fungi and bacteria

Multiple Choice c 3. Trichinella spiralis is a roundworm which may be found in

a. seafood b. poultry c. mammals d. insects

b 4. The disease caused by Trichinella spiralis is known as

a. the flu b. trichinosis c. trichinitis d. salmonellosis

d 5. To kill Trichinella spiralis, food must be cooked to at least

a. 130° F (54ºC) b. 148° F (64ºC) c. 112° F (44ºC) d. 142° F (61ºC)

d 6. Which of these is not a common symptom of Trichinella spiralis infection?

a. vomiting b. abdominal pain c. nausea d. severe headache

Discussion

5

7. Briefly discuss why Trichinella spiralis has been largely eradicated in the United States.

Trichinosis was strongly linked to slop-feeding pigs. Since market hogs have not been slop-fed for several years, trichinosis has been largely eradicated in the U. S.

6


True or False F 1. Symptoms of Hepatitis A infection appear almost immediately. Symptoms appear within 15 to 50 days. T 2. Contaminated water supplies are a possible source of viral food-borne T 3. Humans are the only known host of the Norwalk virus. F 4. The Norwalk virus cannot withstand freezing or chlorine sanitizing The Norwalk virus can survive both freezing and sanitizing. F 5. Hepatitis A and Norwalk viruses can easily survive normal cooking

temperatures. Both viruses are killed during normal cooking temperatures.

Short Answer

6. Symptoms of Hepatitis A infection include inflammation of what organ? liver

7. Name two common symptoms of Hepatitis A and Norwalk virus infections. fever, nausea, abdominal pain

7


True or False F 1. Individual mold plants can easily be seen with the naked eye.

Colonies can be seen with the eye, but individual plants can only be seen through a microscope.

T 2. Molds form spores as a means of reproduction. F 3. Yeasts and molds are a major cause of food-borne illness. Yeast and mold rarely cause food-borne illness. F 4. Molds are easily killed by freezing. Freezing slows down or halts growth, but does not kill mold. T 5. Yeasts and molds (but not necessarily their toxins) can be killed by heating to

140° F (60ºC) for 15 minutes. (Teacher Note: Molds are killed at 140°F (60ºC) for 10 minutes; yeast is killed at 136°F (58ºC) for 15 minutes. Therefore, a temperature of 140° (60ºC) for 15 minutes will kill both mold and yeast.) Short Answer

6. Name two cheeses in which molds are desirable. brie, bleu cheese, camembert

7. What two nutrients do yeast require to survive? sugar and moisture

8. Name two foods in which yeasts are most likely to cause spoilage. fruit juices, jams, jellies, honey

8


Multiple Choice d 1. Which of the following is not a common symptom of most bacterial food-borne

illnesses? a. nausea b. vomiting c. headache d. cough

a 2. Which of the following bacteria does not produce a toxin? a. Salmonella b. Staphylococcus aureus c. C. botulinum d. E. coli

c 3. Which of the following is a spore-forming bacteria?

a. E. coli b. Salmonella c. C. perfringens d. C. jejuni

b 4. Which of the following bacteria is not classified as facultative?

a. Staph b. C. botulinum c. L.monocytogenes d. E. coli

Short Answer

5. Which bacteria is associated with improper canning? Clostridium botulinum (botulism)

6. Which bacteria is a major concern to pregnant women?

Listeria monocytogenes

7. Which bacteria is the most infectious, requiring only a few organisms to cause illness?

Shigella

9

8. Which bacteria causes the largest percentage of bacterial food-borne illness?

Staphylococcus aureus

(Teacher Note: the video says to refer back to 5A if students miss this question. A better spot is in 5B ( you may want to stop here during the showing of the video) where the speaker says that “over the years Salmonella has ranked second behind staph…” Help students realize that this means Staphylococcus aureus is the most common cause of food-borne illness.)

9. Which bacteria has the highest mortality rate? Clostridium botulinum

10. Which bacteria is classified as anaerobic? Clostridium botulinum

10


True or False F 1. E. coli bacteria are found only in the feces of cattle. E. coli is also found in the human intestinal tract. T 2. Staph bacteria can be found in cut and skin lesions. F 3. Bacteria found on and in our bodies are responsible for most food-related

illnesses. Not true. We become ill when we ingest (eat) large amounts of these bacteria or their toxins.

T 4. Keep hot foods hot and cold foods cold. Discussion

5. Briefly discuss the six steps that help reduce the risk of food-borne illness.

Proper handling: wash (and scrub) all food items, use gloves when appropriate.

Proper storage: removed meats from their air-perforated wrappings and rewrap in air-proof wrappings before freezing. Store meats in the refrigerator only 2-3 days. Wrap all foods. Keep vegetables and meats separated.

Proper cooking: cook meats to correct internal temperatures (package or cookbook should tell you). Be especially careful to cook ground meats until brown and juices run clear (160° F, 71ºC).

Prevent cross-contamination: Don’t place raw and cooked meats on the same platter. Use a clean side of the cutting board for cutting up new food items, keep hands from foods, make sure raw meat juices don’t spill onto vegetables. Don’t wash vegetables in a sink that held meat. And other precautions.

Temperature: cooking meats to the right temperature (check cook book or meat package) will kill most harmful bacteria, viruses, fungi, and parasites. Meats like steaks and roasts are easier to wash or wipe off or kill with heat because bacteria doesn’t penetrate far into the meat fibers. However, ground meats are often a combination of meats and often have

11

a lot of “surface bacteria” that has been mixed with it. Cooking thoroughly is very important. No pink meat or juices should be present.

Personal hygiene: wash your hands well and often while preparing food. Always wash with soap and water after using the bathroom. Don’t brush back your hair, pet the dog, nibble on pieces of raw vegetables by picking it up with your hands, and so on. Don’t sneeze or cough on food.

Scenarios The videotape contains three scenarios that show typical food preparation scenes. For each scene, write the problem that may cause food-borne illness and the solution. Scenario # 1: Cook cuts chicken into pieces, then takes the same knife and begins cutting the fat from a piece of red meat.

Problem: Raw chicken usually contains large amounts of bacteria (video mentions that of chicken tested, 50% had salmonella and 80% had Campylobacter jejuni, and poultry is included in most “sources” mentioned for other bacteria in the video). The cook has just transferred bacteria to the meat by using the same knife.

Solution: Use a new knife to cut different food items, or wash knife in between.

Scenario # 2: Food service employee uses the bathroom (you can hear a toilet flushing), checks his hair in the mirror, then leaves.

Problem: The employee may have brought contamination into the bathroom already (and how many did so before him?). Also, it is not that hard to pick up bacteria when you wipe yourself after using the toilet. This is where much hepatitis A and E. coli is picked up. The germ-laden employee (who also picked up a few bacteria when he ran his hand over his hair and from the doorknob) is now going to return to work. Would you want him to fix your next hamburger patty?

Solution: Because bacteria and germs are everywhere, we naturally pick them up as we go about our day. We should always make it a practice to wash our hands after using the bathroom. But for those who work in the food industry, hand washing is vital so they don’t pass on bacteria, fungi, or viruses to their customers. Simple hand washing (soap and water) is the best preventative of food-borne pathogens passed on during food preparation.

Scenario # 3: Cook is shown cutting up potatoes. (Note: students should be able to view the scenario and determine the potential hazards present.)

12

Problem: Potatoes pick up C. botulinum bacteria from the soil, as do carrots and other root crops. Unless the cook washes and scrubs the potato, the bacteria may be dispersed as the knife cuts into the skin and passes down through the potato inside.

Solution: Scrub your vegetables (and fruits) with a vegetable brush to remove bacteria or pesticides. Be aware that root vegetables are grown in a botulism medium, so they need to always be scrubbed. Wash the sliced up potato as well. Don’t pick up and eat raw potato pieces unless you have thoroughly washed them.

13

14


Short Answer 1. What class of animals is the most common host of Trichinella spiralis? mammals 2. Which virus usually causes the common stomach flu or "24-hr. bug”? Norwalk virus 3. Name the two types of fungi associated with food-borne illness. molds, yeast 4. Which group of food-borne pathogens causes most cases of food-borne illness? bacteria 5. Which bacteria are known for rapid multiplication? Clostridium perfringens 6. Which bacteria are the most deadly? Clostridium botulinum 7. Which bacteria can cause miscarriage or abortion in pregnant women?

Listeria monocytogenes 8. Why are bacteria that produce toxins especially dangerous?

Toxins are usually odorless, flavorless, and colorless -toxins are usually heat stable, even if the bacteria is killed by cooking.

9. Which two bacteria are commonly found on and in our bodies?

Escherichia coli and Staphlococcus aureus 10. What personal hygiene practice is most important in preventing food-borne illness? hand washing

understanding food-borne pathogens - career and technical

Documents