Distribution of Toxoplasma gondii tissue cysts in commercial cuts of pork.

Distribution of Toxoplasma gondii cysts in tissues used for human consumption was studied in 4 naturally infected pigs (acquired infections) and in 2 experimentally infected pigs. On the day of euthanasia, pigs with acquired toxoplasmosis had serum antibody titers of 160 to 1,280 against T gondii (modified agglutination test). Experimentally infected pigs were inoculated with 10,000 oocysts of the GT-1 strain of T gondii and were euthanatized 267 or 357 days after inoculation. On the day of euthanasia, the experimentally infected pigs had serum antibody titers of 16 and 32 against T gondii. Fifty- to 100-g specimens from each of 6 cuts of meat commercially used to prepare Boston butt, arm picnic, ham, tenderloin, spareribs, and bacon and from the tongue, heart, brain, liver, kidneys, and diaphragm were collected from each pig and were digested in acid pepsin solution. Washed sediment from the digest of each specimen was inoculated SC into mice (6 mice/organ). Toxoplasma gondii was isolated from tissues of the 4 pigs with acquired toxoplasmosis; T gondii was isolated from the arm picnic, Boston butt, and tongue of 3 pigs, from the ham, tenderloin, spareribs, diaphragm and heart of 2 pigs, and from the bacon and brain of 1 pig. Toxoplasma gondii was not isolated from the kidneys of the 4 pigs with acquired toxoplasmosis. Toxoplasma gondii was isolated from the arm picnic, Boston butt, ham, spareribs, bacon, tongue, diaphragm, heart, and brain of the 2 experimentally infected pigs, and from the kidneys of one of the experimentally infected pigs.(ABSTRACT TRUNCATED AT 250 WORDS)