Quantitative Detection of Staphylococcal Enterotoxin B in Food by Gel-Diffusion Methods

Abstract

RECOVERY of coagulase-positive StaphyloCOCCUs aureus from food implicated in a foodpoisoning outbreak is only circumstant.,ial evidence that the correct etiological agent has been found. Even the determination by animal studies that the strain isolated is capable of producing enterotoxin doeis not prove that it did so in the food. Positive proof depends on demonstration of the enterotoxin in the food itself. Such proof can be obtained by feeding the food to monkeys or human volunteers, but the results are subject to the variations in susceptibility known to occur among both test subjects. The purification (1) of Enterotoxin. B, S6 type [E type of Casman (2) ] and t,he determination that it was an antigenically act-ive protein (.3-5) opened t.he way to use of serologic methods for direct detection of enterotoxin in foods. Although Enterotoxin B occurs in food infrequently (2,6) compared with the frequency of Enterotoxin A, 196E type [F type of Casman (2)], it is a useful substitute for preliminary studies because it can be produced in a highly purified form. This report deals with the results obtained and the difficulties encountered in the use of the various gel-diffusion techniques for the, direct serologic detection and quantification of 'Enterotoxin B in foods.