Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: April 30, 2000
Publication Date: N/A
Technical Abstract: Ingestion of tissue cysts in uncooked, infected meat and oocysts in food or water contaminated with cat feces are the 2 major routes for transmission of T. gondii. Meat from both acutely and chronically infected animals can be a source of infection for humans. Tissue cysts probably survive for the life of the host. Among food animals, T. gondii is more prevalent in the tissues of sheep, goats, pigs, and feral chickens than in tissues of cattle, buffaloes, horses, and battery-raised chickens. Meat from wild animals is also a potential source of human infection. The risk of acquiring T. gondii may vary with the cultural habits of people and animal husbandry methods. In the United States and probably in Europe, pigs are considered an important meat source of T. gondii infection for humans. In pigs and lambs, T. gondii has been found in most edible parts. Therefore, any edible tissue from an infected animal should be considered a apotential source of infection. Tissue cysts are probably killed by commercial procedures of salting and curing. Gamma irradiation (1.0 kGy) already approved by the U.S. Food and Drug Administration will kill tissue cysts in meat; at this dosage of irradiation, the quality of the meat is not affected. Tissue cysts survive in meat stored at 1 to 22 C so long as the meat remains fit for human consumption. Cooking meat in a conventional oven kills tissue cysts, provided the internal temperature reaches 66 C. Longer periods will be needed to inactivate T. gondii at lower temperatures. Microwave cooking cannot be relied upon to kill T. gondii. Freezing meat overnight in a domestic freezer (-8 t0 -12 C) will kill most T. gondii tissue cysts.