Assay of Staphylococcal Enterotoxin from Cheese

5Iethods have been developed for the assay of enterotoxins A and B from cheese using single-or double-gel diffusion procedures. For enterotoxin assay by single diffusion, cheese is blended with veronal buffer, centrifuged, the supernatant fluid filtered, acidified, reeentrifuged, m~utralized, heated, centrifuged again, and the supernatant fluid used as an antigen for gel diffusion. This procedure can be used to quantitatively assay enterotoxin A or B in cheese when the enterotoxin levels are greater than 1 /~g per gram. A procedure was developed for eoneentrating enterotoxin in cheese extracts so that lower concentrations could be detected. When this was used, respective enterotoxin A and B levels as low as 0.02 and 0.05 ~g per gram of cheese were demonstrated, using the double diffusion assay procedure.