The staphylococcal enterotoxins are proteins produced by staphylococci in foods and culture media under certain conditions. Staphylococcal food poisoning is caused by ingestion of enterotoxin. Therefore, diagnosis of staphylococcal food poisoning must be made by detecting enterotoxin in the incriminated foodstuff or cultures of strains isolated from the foodstuff and patients. Specific, highly potent anti-enterotoxin sera are necessary for such examinations. The staphylococcal enterotoxins have been classified into five types, A to E, on the basis of antigenicity.
The methods for purification of enterotoxins reported by many invesigators are rather complicated and different from one type to another. To prepare anti-enterotoxin serum, a large amount (a few to tens of milligrams) of enterotoxin used to be divided into several doses and injected into a rabbit.
The authors purified enterotoxins A and C by the same simplified method consisting of successive chromatography on CM-Sephadex and DEAE-Sephadex and gel filtration on Sephadex G-75. Each rabbit was injected subcutaneously twice with 10-μg doses of purified enterotoxin A or C to prepare anti-enterotoxin serum. The resulting anti-enterotoxin sera were highly specific with potencies high enough to be used for detection and identification of enterotoxins.