Take Precautions to Avoid Contaminated Food

by Diane, M.P.H, M.S.

The Centers for Disease Control and Prevention (CDC) reports that every year one out of six Americans gets sick from foodborne illness. Of those people, 128,000 are hospitalized, and thousands die. Reported outbreaks represent just the tip of the iceberg. Due to public concern about this issue, in 2009 the Center for Science in the Public Interest (CSPI) compiled a list of foods regulated by the U.S. Food and Drug Administration (FDA) that are most likely to infect people with foodborne diseases, such as salmonella, Escherichia coli, and listerimonocytogenes. Experts still consider this a relatively reliable list of the riskiest food items.

The CSPI report analyzed only those foodborne illness outbreaks that have been definitively linked to FDA-regulated products between 1990 and 2006.

The 10 foods regulated by the U.S. FDA (1990-2006) which are most prone to contamination:

  • Leafy Greens: 363 outbreaks involving 13,568 reported cases of illness
  • Eggs: 352 outbreaks involving 11,163 reported cases of illness
  • Tuna: 268 outbreaks involving 2,341 reported cases of illness
  • Oysters: 132 outbreaks involving 3,409 reported cases of illness
  • Potatoes: 108 outbreaks involving 3,659 reported cases of illness
  • Cheese: 83 outbreaks involving 2,761 reported cases of illness
  • Ice Cream: 74 outbreaks involving 2,594 reported cases of illness
  • Tomatoes: 31 outbreaks involving 3,292 reported cases of illness
  • Sprouts: 31 outbreaks involving 2,022 reported cases of illness
  • Berries: 25 outbreaks involving 3,397 reported cases of illness

Illnesses caused by the above foods may be as minor as stomach cramps and diarrhea for a day or two, or as serious as kidney failure or death. Pathogens most commonly associated with meat and poultry, such as Salmonella and E. coli O157:H73, also have been repeatedly linked to these foods. In fact, Salmonella was identified as the cause in 33 % of the outbreaks from the FDA Top Ten. Other pathogens causing outbreaks associated with these foods include Campylobacter, Scombrotoxin, Norovirus, and Vibrio.

Why so much contamination?

  1. Leafy greens (spinach, romaine lettuce, arugula, etc.): Leafy greens were responsible for 24% of all food-related outbreaks between 1990-2009. They are often grown on large fields which are susceptible to E. coli contamination from grazing animals and their manure or contaminated irrigation water. Instead of buying pre-bagged lettuce which includes leaves culled from thousands of different heads of lettuce, any of which could be contaminated, buy one head of lettuce or a three-pack of romaine hearts and prepare it yourself.
  2. Eggs: According to the CSPI, eggs were responsible for 11,163 foodborne illnesses between 1990-2009, mostly due to salmonella. The problem is that eggs can easily become contaminated while still inside the chicken, if the hen is infected. They can also become infected in the hen house. To protect yourself, small children, and elderly adults in your home, always refrigerate eggs as soon as possible. Add eggs, other dairy products, and meat items to your grocery cart last and go directly home afterward. Avoid undercooking eggs when preparing them over-easy, soft-boiled, or poached. The U.S. Department of Agriculture (USDA) recommends that eggs be cooked until the yolk and white are firm and egg dishes should be cooked to an internal temperature of 160°. Another way to be safe is to choose pasteurized liquid eggs, because the heat from the pasteurization process kills any bacteria and viruses.
  3. Tuna: Associated with high mercury levels and foodborne diseases. According to the CSPI report, fresh tuna has been linked with 269 outbreaks involving 2,341 reported cases of illness between 1990-2009 and is the third most contaminated food. Tuna can be contaminated with a toxin known as scombrotoxin, which can form if fish is not kept cool enough after harvesting, during processing, or shipping. Unfortunately, cooking tuna to a safe internal temperature doesn’t eliminate the presence of this toxin once formed. To decrease your risk, purchase tuna from a reputable seafood supplier, and store raw tuna at a temperature of 40° or less until just before cooking.
  4. Oysters: According to the CSPI list, between 1990-2009, oysters accounted for 132 outbreaks involving 3,409 cases of illness, mostly attributed to two sources: norovirus (which is generally spread by contaminated water or surfaces) and vibrio (a dangerous bacteria in the cholera family). Always follow precautionary measures, especially when eating oysters raw. Only eat oysters from the Pacific Northwest or New England, colder waters where bacteria can’t survive. Avoid oysters from the Gulf Coast region or any from warmer waters. When served or sold raw, oysters should be marked with the region of origin. If it’s unclear or not indicated, ask your waiter or store’s fish monger. To be safe, cook all seafood before consuming and avoid raw oysters, when possible.
  5. Potatoes: Responsible for 108 outbreaks involving 3,659 reported cases of illness between 1990-2009 due most often to salmonella and E. coli. The problem is not potatoes themselves, but the dishes they are used in. The most common culprit is potato salad, which people often don’t store properly. Potato salad should be transported in a cooler with ice packs or kept in the refrigerator until just before serving. If you plan to serve it at a buffet, serve it on ice. Use store-bought mayonnaise instead of homemade, if you’re going to transport and serve it, since the former is less likely to get bacteria. A similar problem occurs with mashed potatoes and baked potatoes. If they are allowed to sit around warm, the risk of foodborne illness increases. Keep them at a hot enough temperature, eat them quickly, or refrigerate them.
  6. Cheese: Accounted for 83 outbreaks involving 2,761 reported cases of foodborne illness from 1990-2009. Avoid unpasteurized and raw milk cheeses which are often sold in specialty shops, since many cases of foodborne illness are due to consumption of unpasteurized cheese. Read the package label to determine if the cheese has been pasteurized. Store cheese in the refrigerator either in the original bag or in an air-tight food storage container. Soft cheeses like Feta, Brie, Camembert, etc. and shredded cheeses should not be left out or stored at room temperature for more than 2 hours; discard if left out past 2 hours. An additional concern regarding soft cheeses is that they can become contaminated with listeria, a type of bacteria, after the pasteurization process. Since these types of cheeses are not usually cooked prior to serving, the CDC recommends that pregnant women avoid consuming them, since infection can be harmful to the fetus and lead to serious complications.
  7. Ice Cream: More than half the time, ice cream that causes foodborne illness is associated with private homes and homemade ice cream made with raw eggs and/or raw milk. According to the CSPI, from 1990-2009, ice cream accounted for 74 outbreaks involving 2,594 illnesses between 1990-2009. To protect yourself, make ice cream with pasteurized eggs, available in the shell or liquid form. Pregnant women should avoid both homemade and soft-serve ice cream, because listeria is hardy, able to live on metal, and thus thrive inside soft ice cream machines, which are impossible to clean effectively.
  8. Tomatoes: Unlike other raw produce, which is usually exposed to contaminants during the handling process, tomatoes can be contaminated at just about any point from the field to manufacturer, which makes them particularly risky. In fact, tomatoes are most often contaminated as they grow, when salmonella enters a tomato plant through its roots, flower, or small cracks in the skin or stem. According to the CSPI list, tomatoes accounted for 31 outbreaks involving 3,292 reported cases of illness from 1990-2009. Tomatoes can be contaminated in the field or by cross-contamination during harvest, washing, transport or in the home. Even cut tomatoes support the growth of salmonella and other pathogens. To reduce your risk of exposure, always wash tomatoes well before use, and slice them on a disinfected cutting board, not one that’s used for meat or dairy. Promptly refrigerate any leftover sliced tomatoes. 
  9. Raw sprouts: Although a nutritious addition to salads and sandwiches, the FDA reported 31 outbreaks involving 2,022 cases of illness from 1990-2009 involving both salmonella and E. coli, so they remain a concern for food safety experts. Avoid raw sprouts. The sprout industry has been unable to ensure sprout safety because of the way they are grown. One problem is that contamination may involve the seed itself. Sprout seeds can contain pathogens. If they do, the pathogens multiply during the sprouting process. If you choose to consume them raw, look for signs that they have been improperly handled, such as wilted or soggy sprouts, or any signs of spoilage. Wash them thoroughly and refrigerate them once you get home.
  10. Berries (especially strawberries and imported raspberries): Have caused 25 outbreaks with more than 3,300 sicknesses between 1990-2009, mostly due to cyclospora, a parasitic illness of the intestines. Berries can be exposed to germs and bacteria during processing and handling by an infected worker. Whether picking berries in the field or buying them at a grocery store, it’s important to keep them cold, get them home, and refrigerate them within 2 hours. Place berries in their own separate sealed container in the refrigerator and store on a shelf above raw meats to avoid cross-contamination. Before you eat them, thoroughly wash them under cool running water.
  11. Meat and poultry: Though not on the CSPI list since the FDA doesn’t regulate them, meat and poultry are included on the CDC list of commonly contaminated foods. Undercooked meats account for about 20%-30% of foodborne illnesses reported annually. The most common pathogen found in beef is E. coli O157:H7, while salmonella serovars are more common in poultry. Always use a thermometer when cooking meat to determine whether it has reached a safe internal temperature. Beef, pork, lamb, and veal steaks, chops and roasts should be cooked to a minimum internal temperature of 145°; ground meats (beef, pork, lamb, veal) should be cooked to 160°; chicken and turkey, including ground varieties, should be cooked to 165° before consumption.
Always take precautions to decrease your risk of foodbourne illness.
  1. Gekas, Alexandra. “The 11 Most Contaminated Foods.” Woman’s Day: Healthy Living. 2014.
  2. “The Ten Riskiest Foods Regulated By The U.S. Food And Drug Administration.” Center for Science in the Public Interest (CSPI). The FDA Top Ten /Report was researched and written by Sarah Klein, Jacqlyn Witmer, Amanda Tian, and Caroline Smith DeWaal. CSPI is a non-profit organization based at 1875 Connecticut Ave NW, Suite 300 Washington, DC, 20009. Phone (202) 332-9110 (Source: www.cspinet.org).

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