Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/2005
Publication Date: 11/5/2005
Citation: Lindsay, D.S., Collins, M.V., Holliman, D., Flick, G.J., Dubey, J.P. 2005. Effects of high pressure processing on toxoplasma gondii tissue cysts in ground pork. Journal of Parasitology. 92:195-196.
Interpretive Summary: Toxoplasma gondii is a single-celled parasite of all warm-blooded hosts worldwide. It causes mental retardation and loss of vision in children, and abortion in livestock. Cats are the main reservoir of T. gondii because they are the only hosts that can excrete the resistant stage (oocyst) of the parasite in the feces. Humans become infected by eating undercooked meat from infected animals and food and water contaminated with oocysts.Scientists at the Beltsville Agricultural Research Center and Virginia Tech. report killing of Toxoplasma cysts in meat by high pressure treatment. The results will be of interest to biologists, parasitologists, and veterinarians.
Technical Abstract: Ingestion of Toxoplasma gondii tissue cysts can result in severe disease in immunocompromised individuals and pregnant women. Treatment of meat and meat products to eliminate viable T. gondii tissue cysts would provide a means to protect consumers. The present study examined the effects of high pressure processing (HPP) on ground pork containing viable tissue cysts of the VEG strain of T. gondii. Ground pork containing tissue cysts was exposed to 400 MPa, 300 MPa, 200 MPa, 100 MPa, or no MPa treatment for 30 sec, 60 sec, or 90 sec in a commercial HPP unit. The HPP treated ground pork was subjected to acid-pepsin digestion and bioassayed in mice. The results of the mouse bioassay revealed that none of the mice inoculated with tissue cysts exposed to 400 MPa or 300 MPa became infected, while all mice inoculated with tissue cysts exposed to 200 MPa, 100 MPa, or no MPa became infected with T. gondii regardless of exposure time. Results indicate that HPP treatment of ground pork with 300 MPa of pressure will render tissue cysts of T. gondii nonviable and make pork safe for human consumption.