title: Detection and survival of Toxoplasma gondii in milk and cheese from experimentally infected goats.
abstract: The consumption of unpasteurized goat cheese and goat's milk has been suggested as a risk factor for toxoplasmosis in humans. In the present study, detection and survival of Toxoplasma gondii in milk and cheese was studied by bioassay in mice (milk) and in cats (cheese). Eight goats were inoculated orally with 300 to 10,000 oocysts of T. gondii strain TgGoatUS26. Milk samples were collected daily up to 30 days postinoculation and bioassayed in mice and cats. For mouse bioassay, 50 ml of milk samples were centrifuged, and the sediment was inoculated subcutaneously into mice. Mice were tested for T. gondii infection by seroconversion and by the demonstration of parasites. By mouse bioassay, T. gondii was detected in milk from all eight goats. The T. gondii excretion in milk was intermittent. For cat bioassay, 400 ml (100 ml or more from each goat) of milk from four goats from 6 to 27 days postinoculation were pooled daily, and cheese was made using rennin. Ten grams of cheese was fed daily to four cats, and cat feces were examined for oocyst shedding. One cat fed cheese shed oocysts 7 to 11 days after consuming cheese. Attempts were made to detect T. gondii DNA in milk of four goats; T. gondii was detected by PCR more consistently, but there was no correlation between detection of viable T. gondii by bioassay in mice and T. gondii DNA by PCR. Results indicate that T. gondii can be excreted in goat's milk and can survive in fresh cheese made by cold-enzyme treatment. To prevent transmission to humans or animals, milk should not be consumed raw. Raw fresh goat cheese made by cold-enzyme treatment of unpasteurized milk also should not be consumed.
authors.affiliation: U.S. Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Animal Parasitic Diseases Laboratory, Building 1001, Beltsville, Maryland 20705-2350, USA. jitender.dubey@ars.usda.gov.
authors.forename: J P
authors.initials: JP
authors.lastname: Dubey
authors.affiliation: U.S. Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Animal Parasitic Diseases Laboratory, Building 1001, Beltsville, Maryland 20705-2350, USA.
authors.forename: S K
authors.initials: SK
authors.lastname: Verma
authors.affiliation: U.S. Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Animal Parasitic Diseases Laboratory, Building 1001, Beltsville, Maryland 20705-2350, USA.
authors.forename: L R
authors.initials: LR
authors.lastname: Ferreira
authors.affiliation: U.S. Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Animal Parasitic Diseases Laboratory, Building 1001, Beltsville, Maryland 20705-2350, USA.
authors.forename: S
authors.initials: S
authors.lastname: Oliveira
authors.affiliation: U.S. Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Animal Parasitic Diseases Laboratory, Building 1001, Beltsville, Maryland 20705-2350, USA.
authors.forename: A B
authors.initials: AB
authors.lastname: Cassinelli
authors.affiliation: U.S. Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Animal Parasitic Diseases Laboratory, Building 1001, Beltsville, Maryland 20705-2350, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Ying
authors.affiliation: U.S. Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Animal Parasitic Diseases Laboratory, Building 1001, Beltsville, Maryland 20705-2350, USA.
authors.forename: O C H
authors.initials: OC
authors.lastname: Kwok
authors.affiliation: U.S. Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Animal Parasitic Diseases Laboratory, Building 1001, Beltsville, Maryland 20705-2350, USA.
authors.forename: W
authors.initials: W
authors.lastname: Tuo
authors.affiliation: Division of Applied Veterinary Research, Office of Research, HFV-520, Center for Veterinary Medicine, U.S. Food and Drug Administration, MOD II - 8401 Muirkirk Road, Laurel, Maryland 20708, USA.
authors.forename: O A
authors.initials: OA
authors.lastname: Chiesa
authors.affiliation: Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, 1600 Clifton Road, Mailstop A-06, Atlanta, Georgia 30333, USA.
authors.forename: J L
authors.initials: JL
authors.lastname: Jones
mesh_terms: D000818:Animals; D002415:Cats; D002611:Cheese / Q000469:parasitology*; D005243:Feces / Q000469:parasitology; D005260:Female; D005506:Food Contamination / Q000032:analysis*; D016266:Food Parasitology; D006041:Goats; D006801:Humans; D051379:Mice; D008892:Milk / Q000469:parasitology*; D033661:Oocysts; D016133:Polymerase Chain Reaction; D014122:Toxoplasma / Q000235:genetics* / Q000302:isolation & purification* / Q000502:physiology; D014124:Toxoplasmosis, Animal / Q000469:parasitology