title: Effects of time and temperature on the viability of Toxoplasma gondii tissue cysts in enhanced pork loin.
abstract: Enhanced or pumped pork products represent a significant proportion (40 to 50%) of the commercially available pork cuts available to consumers at the retail level. In a previous study, pork loins containing viable Toxoplasma gondii tissue cysts were pumped with solutions containing 2% sodium chloride or 1.4% or higher potassium or sodium lactate and stored at 4 degrees C for 7 days. This treatment prevented transmission of T. gondii to cats. In the present study, enhanced pork loins were stored for 0, 8, 16, 24, 32, or 40 h at 4 degrees C and then fed to T. gondii-seronegative cats to determine how quickly the loss of tissue cyst viability occurred. In a second experiment, pork loins collected from pigs experimentally infected with T. gondii were stored at temperatures found in retail meat cases and then fed to T. gondii-seronegative cats to determine the effect of typical meat case storage temperatures on tissue cyst viability. In both experiments, cat feces were examined for 14 days after the infected meat meal to assess oocyst shedding. The results indicate that solutions containing 2% sodium chloride or 1.4% potassium or sodium lactate are effective within 8 h of injection for killing T. gondii tissue cysts in pork loins and that storage at meat case temperatures at or below 0 degrees C (32 degrees F) for 7 days also killed T. gondii tissue cysts in pork loins.
authors.affiliation: U.S. Department of Agriculture, Agricultural Research Service, Animal and Natural Resources Institute, Animal Parasitic Diseases Laboratory, BARC-East, Beltsville, Maryland 20705, USA. dhill@anri.barc.usda.gov
authors.forename: D E
authors.initials: DE
authors.lastname: Hill
authors.forename: S M C
authors.initials: SM
authors.lastname: Benedetto
authors.forename: C
authors.initials: C
authors.lastname: Coss
authors.forename: J L
authors.initials: JL
authors.lastname: McCrary
authors.forename: V M
authors.initials: VM
authors.lastname: Fournet
authors.forename: J P
authors.initials: JP
authors.lastname: Dubey
mesh_terms: D000818:Animals; D001681:Biological Assay; D002371:Cat Diseases / Q000469:parasitology / Q000635:transmission; D002415:Cats; D003257:Consumer Product Safety; D005511:Food Handling / Q000379:methods*; D016266:Food Parasitology; D005519:Food Preservation / Q000379:methods*; D005520:Food Preservatives / Q000494:pharmacology*; D007773:Lactates / Q000494:pharmacology; D008460:Meat / Q000469:parasitology*; D012965:Sodium Chloride / Q000494:pharmacology; D013552:Swine; D013553:Swine Diseases / Q000469:parasitology / Q000635:transmission; D013696:Temperature; D013997:Time Factors; D014122:Toxoplasma / Q000187:drug effects / Q000254:growth & development*
chemical_list: D005520:Food Preservatives; D007773:Lactates; D012965:Sodium Chloride