What are common food-borne illnesses and how do I prevent contraction?

Oct 23, 2015

Food poisoning is an illness caused by the consumption of foods containing toxins produced by bacteria. Toxin producing bacteria that can grow in meat include Clostridium botulinum, Staphylococcus aureus, and clostridium perfringens. Infections occur from eating meat or other protein foods that contain organisms which multiply in the instetinal tract (Salmonella and Listeria monocytogenes) or from parasites (Trichinella spiralis).  Proper food preservation, preparation and storage techniques minimize the possibility of food poisoning and food infection.

 Food Poisoning

 Clostridium botulinum- Botulism, the most serious from of food poisoning, is caused by various strains of Clostridium botulinum, which produce toxins that attack the human central nervous system. Symptoms begin to be noticeable about 12 to 48 hours after consumption of contaminated food, for example, muscular weakness, and loss of those functions which are dependent on nerve action. About two thirds of the cases are fatal. Botulism is most often associated with improper caning of low-acid (high pH) fruits and vegetables. Clostridium botulinum is an anaerobic bacteria and can grow in canned and vacuum packed foods including meat; however because the distribution of spores in meat is usually very low, botulism from meat sources is rare. Special care should be taken in preparing all hone-canned foods, including meat.

 Cans of food that show evidence of swelling or seepage should be destroyed. Processed, pre-cooked frozen, or frozen uncooked meat should not be allowed to stand at room temperature for extended periods of time. Cooking for 10 minutes at 176°F inactivates potentially harmful toxins; however longer cooking times at higher temperatures are necessary to completely destroy botulism spores. Nitrite is added to processed meat to inhibit the reproduction of Clostridium botulinum spores.

 Staphylococcus aureus- Staphylococcal food poisoning is serious but rarely fatal. It is caused by the heat-stable toxin produced by the bacteria Staphylococcus aureus, which can contaminate high protein foods such as meat, eggs, milk and custards. The flavor, appearance, and aroma of contaminated food may not be noticeably affected. The bacteria can be easily transferred from humans to meat during handling. However, the most common way Staphylococcus aureus toxins are produced is when cooked meat is handled and then left at room temperature for an extended period of time (over two hours). Once formed, the toxin-producing bacteria cannot be destroyed by reheating the meat. Two to six hours after eating the contaminated food, an infected individual experiences nausea, vomiting, and abdominal pains. The illness usually lasts one to three days.

 Clostridium perfringens- Clostridium perfringens may be found in fresh meat and meat-based sauces or gravies, especially if they are allowed to cool slowly after cooking. Symptoms are nausea, occasional vomiting, diarrhea and abdominal pain eight to 24 hours after eating. Clostridium perfringens food poisoning can be controlled by careful sanitation practices, and the rapid cooling and refrigeration or cooked foods.

 Food Infections

 Salmonella species- Salmonellosis is the most common food-borne infection in the United States. It results from eating food containing living organisms of the genus, Salmonella. Salmonella species grow rapidly in contaminated protein foods, especially if they are held at room temperature or kept warm for several hours.

Symptoms of salmonellosis (nausea, vomiting, diarrhea, fever and abdominal pains) are thought to be caused by the toxin produced in the digestive tract of infected individuals. The number of organisms ingested must be high (about one million) for clinical symptoms to occur. Several days may pass between the ingestion of a contaminated food and the presence of symptoms; however, the normal incubation time is 12 to 24 hours.

 Listeria monocytogenes- Listeria monocytogenes is a widely distributed pathogen that can be transmitted to humans through contamination of food stuffs at any point in the food chain. Several major food commodities are implicated: milk and dairy products, meat (especially raw meat products), poultry and its products, vegetables, salads and seafood. Unlike most other food-borne pathogens, Listeria is able to multiply at refrigeration temperatures, 40°F to 43°F. Furthermore, Listeria monocytogenes is about four times more heat-tolerant than Salmonella and it flourishes in wet conditions.

 Proper heat treatment and refrigeration can reduce the number of Listeria monocytogenes organisms but recontamination can occur during further manipulation of the products, particularly those foods which are not aseptically packaged immediately after listericidal treatment. The risk of contamination can be reduced by adherence to good hygiene practices in food manufacturing establishments, retail establishments and the home.

 Source: Lessons on Meat

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