Evaluation of the VIDAS staph enterotoxin II (SET 2) immunoassay method for the detection of staphylococcal enterotoxins in selected foods: collaborative study.

ABSTRACT

A multilaboratory study was conducted to determine the limit of detection (LOD) of Staphylococcal enterotoxins (SET) in 5 foods. Cooked chicken, ham, potato salad, pasteurized liquid whole milk, and canned mushrooms were each spiked with a different enterotoxin (A, B, C1, D, or E), and tested at 0.25 and 0.5 ng/g SET levels to determine the LOD of the assay for those foods in a collaborative study. Unspiked controls were also included. A total of 19 laboratories representing government and industry participated. In this study, 1674 test portions were analyzed, of which 1638 were used in the statistical analysis. Of the 1638 test portions used in the statistical analysis, 1104 were spiked test portions, of which 1073 were positive by the VIDAS Staph enterotoxin II (SET 2) method. The detection rates at the 0.25 ng/mL level were cooked chicken, 98.2%; ham, 99.0%; potato salad, 99.1%; liquid whole milk, 85.2%; and canned mushrooms, 100%. The detection rates at the 0.5 ng/mL level were cooked chicken, 97.4%; ham, 98.1%; potato salad, 100%; liquid whole milk, 99.0%; and canned mushrooms, 100%. The data indicate that the SET 2 method is capable of detecting SET at 0.25 ng/g in cooked chicken, ham, potato salad, and canned mushrooms and at 0.5 ng/g in pasteurized liquid whole milk.