Occasionally, a federal or state governmental health agency will issue food safety warnings. These are usually of a temporary measure, lasting until the problem is corrected. The warning may involve a local area, state, region, or may involve the entire country. Pay attention to them. These warnings are issued when a food source may have been contaminated. Contamination of foods may be a function of processing (inadequate refrigeration or cooking) or a function of nature (naturally-occurring toxins or germs).
Foods sometimes temporarily listed as potentially dangerous include meats (beef, pork, poultry), shellfish (including oysters, clams and mussels), fish, eggs, and unpasteurized juices and dairy products.
Food contamination is often the result of the growth of harmful bacteria. Salmonella, E. coli, or Campylobacter bacteria are frequent culprits. These bacteria can cause abdominal cramping and diarrhea which usually resolves without treatment. However, sometimes antibiotics are used. Hepatitis A (caused by a virus) is often transmitted through poor handwashing practices in restaurants. Restaurants suspected of spreading Hepatitis A through food are usually closed down quickly. Shellfish occasionally produce substances which act as potent nervous system toxins. Toxoplasmosis may be spread through handling of uncooked meat.
Most foodborne illness will not affect a developing fetus. However, some causes of foodborne illness can produce birth defects or harm the fetus. Mercury (usually in form of methylmercury) is a known teratogen. Fish living in mercury-contaminated water may accumulate dangerous levels of mercury. In February of 2003,the Food Standards Agency (FSA) in Great Britain began advising pregnant and breastfeeding women, and women and women who intend to become pregnant, to limit their consumption of tuna to no more than two medium-size cans or one fresh tuna steak per week. They also advised avoiding eating shark, swordfish and marlin.
The FSA’s 2002 survey revealed relatively high levels of mercury in some types of large predatory fish. The mean levels of methylmercury found included:
- Shark 1.52mg/kg
- Swordfish 1.35mg/kg
- Marlin 1.09mg/kg
- Fresh tuna 0.40mg/kg
- Canned tuna 0.19mg/kg
In March of 2004, the U.S. Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA) announced a joint consumer advisory on methylmercury in fish and shellfish for reducing the exposure to high levels of mercury in women who may become pregnant, pregnant women, nursing mothers, and young children. Here are their recommendations:
- Do not eat Shark, Swordfish, King Mackerel, or Tilefish because they contain high levels of mercury.
- Eat up to 12 ounces (two average meals) a week of a variety of fish and shellfish that are lower in mercury. Five of the most commonly eaten fish that are low in mercury are shrimp, canned light tuna, salmon, pollock, and catfish. Another commonly eaten fish, albacore (“white”) tuna has more mercury than canned light tuna. So, when choosing two meals of fish and shellfish, you may eat up to six ounces (one average meal) of albacore tuna per week.
- Check local advisories about the safety of fish caught by family and friends in your local lakes, rivers and coastal areas. If no advice is available, eat up to six ounces (one average meal) per week of fish you catch from local waters, but don’t consume any other fish during that week.
Also, in Japan, pregnant women do not eat sushi. Raw fish may contain parasites and if inadequately refrigerated may grow harmful bacteria.
If you learn of a food safety warning in your community, call your doctor or midwife to get advice about what you should do.