Evaluation of an immunofluorescence antibody assay for the detection of antibodies against Toxoplasma gondii in meat juice samples from finishing pigs.

Serum and meat juice analyses for the detection of Toxoplasma gondii antibodies by an immunofluorescence antibody assay were compared in 100 seropositive and 100 seronegative slaughtered heavy swine. Meat juice was obtained from diaphragm and gracilis muscles of the serologically tested animals. Seventy-two diaphragmatic meat juice samples (36%, 95% interval confidence [IC] 29.4%-43.1%) and 63 gracilis meat juice samples (31.5%, 95% IC 25.1%-38.4%) tested positive for T. gondii antibodies. The average concordance between serum and meat juice derived from both muscles was "substantial" (K=0.6-0.8). The K-value was 1 when considering serum samples showing a titer >1/16, whereas it decreased to 0.62 and to 0.49 when considering serum samples with a 1/16 titer in meat juice from diaphragm and gracilis muscle, respectively.