These toxins are thought to cause liver cancer and are not easily inactivated by heat achieved during baking. Extremely moldy food should be discarded. In the United States, there are far fewer documented cases of foodborne disease and illness due to parasites than due to bacteria. Parasites can be found in irrigation water, in cat feces in the farm yard, in the muscle tissue of improperly fed and maintained cattle and swine, and in fish muscle. Humans become infected when they eat undercooked meat, poultry, fish and vegetables.
Parasites are hard to detect.
Early symptoms of parasitic illness include loss of appetite and weight loss. Some parasitic illnesses may be treated with medication. The medication causes the parasites to die and they are excreted. In some cases, parasites may need to be removed surgically. Sometimes people complain that they became ill with diarrhea immediately after consuming a food.