Immunoenzymatic detection of staphylococcal enterotoxins: international interlaboratory study.

An international interlaboratory study was performed by 13 laboratories to validate a commercially available, rapid enzyme immunoassay for detection of staphylococcal enterotoxins A, B, C, D, and E in foods. The 5 enterotoxin serotypes were detected at a level of 0.5 ng/g in mushrooms and ravioli, 0.8 ng/g in meat, 1 ng/mL in milk, and 1.5 ng/g in raw milk cheese when these foods were artificially contaminated with enterotoxin A. Enterotoxins A, B, C, D, or E were also detected in culture supernatants with no protein A interference when normal rabbit serum was used. This method was validated by the French Normalization Agency for the identification of staphylococcal enterotoxins in foods and culture fluids.