Causes of Food Contamination
The next time you bite down on a partially cooked hamburger or scoop up lukewarm potato salad, consider the risk to your health. Each year, an estimated 76 million people in the U.S. are sickened by tainted food, according to the Centers for Disease Control and Prevention. Harmful bacteria, viruses and toxins thrive in meats, produce and dairy products when proper food safety isn't practiced. However, understanding the causes of food contamination is one way to help reduce it.
Viruses such as hepatitis A and Norwalk are easily transmitted to shellfish, salads, vegetables and fruits when infected food handlers fail to wash their hands after using the toilet. By touching utensils or food, they pass the virus to others. Food contamination also occurs when workers skip washing their hands after handling raw meat, taking out garbage or cleaning up spills. Germs end up on the buffet table, and then in your mouth when you consume food prepared by negligent workers.
Contamination also spreads when someone has cuts, open sores or a skin infection. For example, Staphylococcus aureus is often found on skin with boils and blisters. Handlers who don't wear gloves commonly spread staph bacteria to meat, cream-filled desserts, potato salads and egg products. Because staph thrives in room temperatures and multiplies without any hint of spoilage, it's important for infected workers to wear gloves. However, touching contaminated surfaces, coughing into a gloved hand or handling money before food preparation can still spread germs, which is why gloves should be changed often.
Lax slaughterhouse practices can lead to contamination, especially when fecal or intestinal matter from cattle mixes with the meat. A small amount can taint an entire batch and spread E. coli O157:H7, commonly found in animals but deadly when consumed by humans. Numerous beef recalls have been linked to this particular strain, which is why people are advised not to eat raw or undercooked ground meat.
Produce can also be affected. Contamination occurs when fruits and vegetables are fertilized with raw manure or when crops are irrigated with water containing traces of animal waste. Spinach and lettuce have been linked to E. coli outbreaks. Even some unpasteurized items, such as fruit juice and milk, carry risks because they haven't been heat-treated to eliminate E. coli bacteria. Drinking pasteurized products and washing produce thoroughly helps protect people from these bacteria.
When grilled meat is dipped in used marinade or juices from raw beef and poultry drip onto cooked items, cross-contamination occurs. When kitchen tools or cutting boards used for raw meat come in contact with other food or serving utensils, bacteria can be transferred. For instance, slicing lettuce with a knife you used to cut raw poultry is just one example of how easily cross-contamination occurs. Washing utensils and cutting boards with hot water and soap between use helps minimize contamination.
Improperly canned food can form deadly toxins. Low-acid vegetables such as green beans, corn, beets and asparagus are commonly associated with botulism poisoning. If you do home canning, strict hygienic procedures must be followed to ensure safety. Recommendations by the U.S. Department of Agriculture include hot packing many foods, using self-sealing lids and sterilizing empty jars. Bulging cans with rusted lids or cracked, leaking jars should be thrown out.
Because bacteria multiply rapidly on prepared stews, meats and gravy left at room temperature, prompt refrigeration of leftovers is crucial. Leaving food out longer than two hours is a prime opportunity for bacterial growth. Uncooked foods such as creamy salads should be eaten immediately or quickly refrigerated. Other perishables such as eggs, which often harbor Salmonella bacteria, should be kept below 40°F to decrease contamination.
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