Evaluation of an alternative extraction procedure for enterotoxin determination in dairy products

A concentration protocol based on trichloroacetic acid precipitation was evaluated and compared with the reference method using dialysis concentration. Different quantities of purified staphylococcal enterotoxins were added to pasteurized Camembert‐type cheeses. Detection of enterotoxins in these cheeses was performed using an automated detection system. Raw goat milk Camembert‐type cheeses involved in a staphylococcal food poisoning were also tested. Both enterotoxin extraction methods allowed detection of the lowest enterotoxin concentration level used in this study (0·5 ng g−1). Compared with the dialysis concentration method, TCA precipitation of staphylococcal enterotoxins was 'user‐friendly' and less time‐consuming. These results suggest that TCA precipitation is a rapid (1 h), simple and reliable method of extracting enterotoxin from food which gives excellent recovery from dairy products.