Production of staphylococcal enterotoxins A, B, and C in various media

The effect of initial pH and of length of incubation time at 37 C in four different growth media on the production of staphylococcal enterotoxins A, B, and C was determined. A starting pH of 6.8 gave higher yields of enterotoxins B and C than either pH 6.0 or 5.3. The production of enterotoxin A was, however, not materially affected by the low initial pH of 5.3. Prolonged incubation (48 to 72 hr) resulted only occasionally in higher yields of enterotoxin. The effect of the media on the amount of enterotoxin produced is considerable. Difco Brain Heart Infusion (BHI) was inferior to either Fisher BHI, 4% NZ Amine (NAK), or 3% NAK plus 3% protein hydrolysate powder at the three initial pH values, regardless of length of incubation time. The slight effect of the low starting pH on the production of enterotoxin A is being further investigated.