PRODUCTION OF STAPHYLOCOCCAL-ENTEROTOXIN-H UNDER CONTROLLED PH AND AERATION

The effects of controlled pH and aeration on the growth of Staphylococ cus aureus strain FRI-569 and production of enterotoxin H (SEH) were s tudied. S. aureus FRI-569 did not grow well anaerobically. Aeration pe rmitted better growth of cells especially at a flow rate of 300 cc/min . The optimal pH for S. aureus FRI-569 growth was 7.0, with less growt h being observed at pH 6.5 and 7.5 or with no pH control. Very little SEH (< 21 ng/ml) was produced by S. aureus strain FRI-569 under anaero bic incubation. High SEH production was observed with aeration at 300 cc/min. Increasing aeration to 400 cc/min or decreasing it to 200 cc/m in resulted in reduced SEH production. Larger amounts of SEH were prod uced when the pH was controlled at 7.0, while maintaining the pH at 6. 5 or 7.5 resulted in lower levels of SEH being produced. However, the amounts were still greater than those observed when the pH was not con trolled. (C) 1998 Elsevier Science B.V.