title: Effect of high temperature on infectivity of Toxoplasma gondii tissue cysts in pork.
abstract: To study the effect of high temperature on infectivity of Toxoplasma gondii tissue cysts, pork from infected pigs was mixed with infected mouse brains and homogenized thoroughly. Twenty-gram samples of infected homogenized meat were sealed in plastic pouches, pressed to a uniform thickness of 2 mm, and subjected to water-bath temperatures of 49, 52, 55, 58, 61, 64, and 67 C for 0.01, 3, 6, 9, 12, 24, 48, and 96 min. Treated samples were digested in HCl-pepsin solution and bioassayed in mice. Toxoplasma gondii tissue cysts remained viable at 52 C for 9.5 min but not for 9.5 min at 58 C; tissue cysts were generally rendered nonviable by heating to 61 C or higher temperature for 3.6 min. Tissue cysts survived once at 64 C for 3 min. These data demonstrate that T. gondii tissue cysts are less heat resistant than encysted Trichinella spiralis larvae.
authors.affiliation: Zoonotic Diseases Laboratory, U.S. Department of Agriculture, Beltsville, Maryland 20705.
authors.forename: J P
authors.initials: JP
authors.lastname: Dubey
authors.forename: A W
authors.initials: AW
authors.lastname: Kotula
authors.forename: A
authors.initials: A
authors.lastname: Sharar
authors.forename: C D
authors.initials: CD
authors.lastname: Andrews
authors.forename: D S
authors.initials: DS
authors.lastname: Lindsay
mesh_terms: D000818:Animals; D005506:Food Contamination / Q000517:prevention & control*; D006358:Hot Temperature; D008460:Meat; D051379:Mice; D012044:Regression Analysis; D013552:Swine; D013553:Swine Diseases / Q000469:parasitology*; D014122:Toxoplasma / Q000502:physiology*; D014124:Toxoplasmosis, Animal / Q000469:parasitology*