People become infected by eating meat containing viable Trichinella larvae, particularly when pork or wild game has not been adequately cooked.
Modern commercial pork production has dramatically reduced the risk in many countries, but infections can still occur, particularly from undercooked wild game such as wild boar.
Symptoms can initially resemble food poisoning, including diarrhea, nausea, and abdominal discomfort. Later, some infections can cause fever, muscle pain, weakness, and swelling around the eyes.
The safest approach is simple: cook pork and wild game thoroughly and use a food thermometer rather than judging doneness by appearance alone.
3. Raw or Undercooked Beef
Beef can also be associated with parasites.
Taenia saginata, commonly called the beef tapeworm, can infect people who consume raw or inadequately cooked beef containing larval cysts.
Some infected people have few or no symptoms, while others may notice abdominal discomfort, digestive changes, or segments of the tapeworm in their stool.
Foods such as steak tartare and very rare beef therefore carry a different risk profile from thoroughly cooked meat.
This does not mean you need to eliminate beef from your diet. Proper cooking, hygienic handling, and purchasing meat from reputable sources substantially reduce the risk.
4. Unwashed Fruits and Vegetables
This one may surprise people because parasites are not always associated with meat.