Comparison of coagulase and thermonuclease activities with enterotoxin production by staphylococci from foods

Abstract Coagulase, DNase and enterotoxin production of 200 strains of staphylococci isolated from various foods were compared in order to see to what extent these biochemical tests can replace the enterotoxin assay for predicting food safety. Any degree of coagulase formation was not indicative of DNase activity also. However, all cultures having a 4+ score of coagulase showed DNase. DNase activity decreased with heating. No correlation could be seen between coagulase and enterotoxin or DNase and enterotoxin production. In fact, a number of coagulase negative strains were found to produce enterotoxins. Reliability of coagulase or DNase activity for predicting food safety is therefore doubtful.