Staphylococcal Enterotoxin B Production in Hard‐boiled Eggs

Enterotoxin B was detected in hard‐boiled eggs that were cooled in water containing <10 2 CFU/ml Staphylococcus aureus strain FRI‐947 and incubated at 37°C for 24 hr. Factors affecting enterotoxin B production were the number of organisms in the cooling water, cooling time, egg temperature and the length of time and temperature at which the eggs were held after cooling. Addition of 1% ovalbumln or conalbumin to 3% protein hydrolysate powder plus 3% N‐Z Amine NAK medium in flasks, incubated with shaking, increased the enterotoxin B production by 10–30% but no enterotoxin was produced in ovalbumin or boiled egg white suspension alone.