Bacteria That Cause Foodborne Illness

BACTERIA THAT CAUSE FOODBORNE ILLNESS

Campylobacter jejuni, Clostridium botulinum, Clostridium perfringens, Cyclospora Cayetanensis, Escherichia coli 0157:H7, Listeria monocytogenes, Salmonella, Shigella, and Staphylococcus aureus are examples of bacteria that can cause foodborne illness. Refer to Table 10-1.

Campylobacter Jejuni

Campylobacter jejuni is believed to be one of the most prevalent causes ofdiarrhea. It is commonly found in the intestinal tracts of cattle, pigs, sheep, chickens, turkeys, dogs, and cats and can contaminate meat during slaughter. It is caused by the ingestion of live bacteria.

It can take from 2 to 5 (or more) days to develop after infection and may last up to 10 days. Symptoms include diarrhea (sometimes bloody), fever, headache, muscle and abdominal pain, and nausea. It can be transmitted to humans via unpasteurized milk; contaminated water; and raw or undercooked meats, poultry, and shellfish.

Clostridium Botulinum

Clostridium botulinum is found in soil and water, on plants, and in the intestinaltracts of animals and fish. The spores of these bacteria can divide and produce toxin in the absence of oxygen. (Spores are single cells that are produced asexually, each of which is able to develop into a new organism. They have thick, protective walls that allow them to survive unfavorable conditions.) This means that the toxin can be produced in sealed containers such as cans, jars, and vacuum-packaged foods.

The spores are extremely heat resistant and must be boiled for 6 hours before they will be destroyed. Such a lengthy time will, of course, destroy the food they have infected. The toxin, however, can be destroyed by boiling for 20 minutes. This toxin causes botulism, which is perhaps the rarest but most deadly of all food poisonings. Symptoms usually appear within 4 to 36 hours after eating and include double vision, speech difficulties, inability to swallow, and respiratory paralysis. If botulism is not properly treated, death will result in 3 to 10 days. The fatality rate in the United States is about 65%.

Great care must be taken to prevent botulism when canning foods at home. The Centers for Disease Control and Prevention (CDC) reported that from 1950 through 1996, 289 botulism outbreaks have been traced to home-processed foods and 31 to commercially processed foods, including foods served in restaurants. The type of food processing was unknown for the remaining 124 outbreaks. Vegetables were the most important carrier for themeans that the toxin can be produced in sealed containers such as cans, jars, and vacuum-packaged foods.

The spores are extremely heat resistant and must be boiled for 6 hours before they will be destroyed. Such a lengthy time will, of course, destroy the food they have infected. The toxin, however, can be destroyed by boiling for 20 minutes. This toxin causes botulism, which is perhaps the rarest but most deadly of all food poisonings. Symptoms usually appear within 4 to 36 hours after eating and include double vision, speech difficulties, inability to swallow, and respiratory paralysis. If botulism is not properly treated, death will result in 3 to 10 days. The fatality rate in the United States is about 65%.

Great care must be taken to prevent botulism when canning foods at home. The Centers for Disease Control and Prevention (CDC) reported that from 1950 through 1996, 289 botulism outbreaks have been traced to home-processed foods and 31 to commercially processed foods, including foods served in restaurants. The type of food processing was unknown for the remaining 124 outbreaks. Vegetables were the most important carrier for thebotulism toxin in the United States during this time period. Raw honey has also been identified as a source. If a can bulges, Clostridium botulinum may be present and can be fatal. A good rule of thumb is: “If in doubt, throw it out” where children and animals cannot reach it.

Clostridium Perfringens

Clostridium perfringens is often called the “cafeteria” or “buffet germ” becauseit tends to infect those who eat food that has been standing on buffets or steam tables for long periods. Clostridium perfringens is found in soil dust, sewage, and the intestinal tracts of animals. It is a spore-forming pathogen that needs little oxygen. The bacteria are destroyed by cooking, but the spores can survive it.

Clostridium perfringens is transmitted by eating heavily contaminatedfood. Symptoms include nausea, diarrhea, and inflammation of the stomach and intestine. Symptoms may appear within 6 to 24 hours of ingestion and last approximately 24 hours.

To best prevent it, hot foods should be kept at or above 140°F and cold foods below 40°F. Leftovers should be heated to 165°F before serving. Foods should be stored at temperatures of 40°F or lower. People with compromised immune systems should be very cautious concerning Clostridium perfringens.

Cyclospora Cayetanensis

Cyclospora cayetanensis is a parasite that causes gastroenteritis. Until 1996most cases were experienced by overseas travelers, but several domestic out-breaks have been reported in recent years. This bacteria is commonly found in the feces of an infected person and can be transmitted by poor hygiene. It has been found in unclean water.

Symptoms are watery diarrhea, abdominal cramps, decreased appetite, and a low-grade fever. These symptoms could last off and on for several weeks. Those with compromised immune systems, children, and the elderly are at greatest risk of complications.

Cyclospora has an incubation period of 1 week, is associated with inva-sion of the small intestine, and is manifested by the preceding symptoms. The parasite’s natural ecology, infective dose, and host range are unknown. It is known that Cyclospora does not multiply outside the host.

It is strongly recommended that clean water be used for drinking and the irrigation of produce. Thorough washing of fruits and vegetables and the practice of good hygiene by food handlers help to prevent the spread of this bacteria.

Escherichia Coli (E. coli 0157:H7)

Escherichia coli, commonly called E. coli, is a group of bacteria that can cause ill-ness in humans. E. coli 0157:H7 is a very infectious strain of this group. These bacteria can be found in the intestines of some mammals (including humans and animals used for food), in raw milk, and in water contaminated by animal or human feces.

E. coli are transmitted to humans through contaminated water,unpasteurized milk or apple juice, raw or rare ground beef products, unwashed fruits or vegetables, and directly from person to person. Plant foods can be con-taminated by fertilization with raw manure or irrigation with contaminated water.

Symptoms include severe abdominal cramps, diarrhea that may be watery or bloody, and nausea. Sometimes, however, E. coli 0157:H7 can cause hemorrhagic colitis (inflammation of the colon). This in turn can result in hemolytic uremic syndrome (HUS) in children, which can damage the kidneys.

E. coli can be controlled by careful choice and cooking of foods. All meatsand poultry should be cooked thoroughly. Ground beef, veal, and lamb should be cooked to 160°F and ground poultry to at least 165°F. Fruits and vegetables should be carefully washed, and unpasteurized milk and other dairy products and vegetable and fruit juices should be avoided. People with compromised im-mune systems should be especially vigilant.

Listeria Monocytogenes

Listeria monocytogenes is a bacteria often found in human and animal intestinesand in milk, leafy vegetables, and soil. It can grow in the refrigerator and can be transmitted to humans by unpasteurized dairy foods such as milk, soft cheeses, and ice creams and via raw leafy vegetables and processed meats.

Listeria monocytogenes can affect a person from 12 hours to 8 daysafter ingestion. Symptoms include fatigue, fever, chills, headache, backache, abdominal pain, and diarrhea. It can develop into more serious conditions and cause respiratory distress, spontaneous abortion, or meningitis.

To prevent infection by Listeria monocytogenes, meats and poultry should be thoroughly cooked and salad greens carefully washed. Attention must be paid to all dairy products—especially the unfamiliar from new sources—to be certain they have been pasteurized.

Salmonellosis

Salmonellosis (commonly called salmonella) is an infection caused by the Salmonella bacteria.Salmonellacan be found in raw meats, poultry, fish,milk, and eggs. It is transmitted by eating contaminated food or by contact with a carrier. Salmonellosis is characterized by headache, vomiting, diarrhea, abdominal cramps, and fever. Symptoms generally begin from 6 to 48 hours after eating. In severe cases, it can result in death. One species of Salmonella causes typhoid fever. Those who suffer the most severe cases are typically the very young, the elderly, and the weak or incapacitated.

Refrigeration (40°F or lower) inhibits the growth of these bacteria, but they can remain alive in the freezer and in dried foods. Salmonella bacteria are destroyed by heating to at least 140°F for a minimum of 10 minutes.

To prevent contamination, thaw poultry and meats in the refrigerator or microwave and cook immediately. Avoid cross-contamination of raw and cooked foods by carefully cleaning utensils and counter surfaces that were in contact with raw food. Raw or undercooked eggs, or foods that contain them,should not be eaten. Even a taste of raw cookie dough or Caesar salad dressing made with raw egg yolk can cause contamination. People with compromised immune systems should be especially careful.

Shigella

Shigella bacteria are found in the intestinal tract and thus the feces of infected in-dividuals. The disease they cause is called shigellosis. These bacteria are typically passed on by an infected food handler who did not wash his or her hands properly after using the toilet. They are also found on plants that were fertilized with un-treated animal feces or given contaminated water. Shigella are destroyed by heat, but infected cold foods such as tuna, chicken, or egg salads are common carriers.

Shigellosis can occur from 1 day to a week following infection. Symptoms include diarrhea (sometimes with blood and mucus), fever, chills, headache, nausea, and abdominal cramps and can lead to dehydration. Some people, however, experience no symptoms.

Staphylococcus Aureus

Staphylococcus aureus bacteria are found on human skin, in infected cuts andpimples, and in noses and throats. Staphylococcal poisoning is commonly called staphylococcus (staph). These bacteria grow in meats; poultry; fish; egg dishes;salads such as potato, egg, macaroni, and tuna; and cream-filled pastries. This poi-soning is transmitted by carriers and by eating foods that contain the toxin these bacteria create.

Symptoms, which include vomiting, diarrhea, and abdominal cramps, begin within ½ to 8 hours after ingestion of the toxin and last from 24 to 48 hours. Staph is considered a mild illness.

The growth of these bacteria is inhibited if foods are kept at temperatures above 140°F or below 40°F. Their toxin can be destroyed by boiling the food for several hours or by heating it in a pressure cooker at 240°F for 30 minutes. Both of these methods would destroy both the appeal and nutrient content of the infected foods. It is more practical to safely discard foods suspected of being contaminated.