Pregnancy affects the immune system, causing both mother and unborn baby to be more susceptible foodborne illness caused by bacteria, viruses, and parasites. Most foods are safe; however, there are some foods that should be avoided during pregnancy. The Mayo Clinic has a a list of these foods that should be avoided during pregnancy.
Seafood that is high in mercury should be avoided during pregnancy. According to the Mayo Clinic, pregnant women should avoid swordfish, shark, king mackerel and tilefish. Avoid all raw fish and shellfish -- especially oysters and clams -- as well as refrigerated, smoked seafood often labeled as lox, nova style, kippered, or jerky as they could contain harmful bacteria and viruses. Canned, chunk light tuna is generally lower in mercury than other tuna, but still should only be consumed in moderation. According to foodsafety.gov, canned smoked seafood is usually OK to eat or if the fish is cooked entirely to 165 degrees Fahrenheit.
Uncooked Meats and Eggs
The Mayo Clinic also notes that undercooked meats, poultry and eggs can contain harmful bacteria such as Listeria, E. coli, Campylobacter and Salmonella, which can cause foodborne illness and should be avoided during pregnancy. According to foodsafety.gov, all meats, including beef, veal, and lamb steaks and roasts should be cooked to 145 degrees Fahrenheit. Pork and ground beef should be cooked to 160 degrees Fahrenheit. Deli meats, meat spreads and hot dogs should be cooked thoroughly or avoided completely. Cook eggs until the egg yolks and whites are firm and avoid foods made with raw or partially cooked eggs.
Unpasterized and Unwashed Foods
According to the Mayo Clinic products that are unpasteurized or are not washed completely can contain Campylobacter, E. coli, Listeria, or Salmonella, which may lead to foodborne illness and should not be consumed when pregnant. Unless the dairy product is clearly labeled as being pasteurized, don't eat it. This may include Brie, feta, Camembert, blue cheese, Roquefort, Gorgonzola and Mexican-style cheeses, homemade ice cream, and unpasteurized juice. Only consume thoroughly washed fruits and vegetables and cut away damaged portions to avoid a potential foodborne illness. Also raw sprouts of any kind.
Alcohol and Caffiene
The Mayo Clinic also notes that there is no amount of alcohol that is known to be safe during pregnancy, and therefore should be avoided altogether. Excess caffeine should also be avoided According to the Mayo Clinic, a large 2008 study suggests that 200 mg of caffeine a day during pregnancy may slow fetal growth. Check with a doctor before drinking herbal tree as the effects of some of these on a fetus are still unknown.