Influence of carvacrol on growth and toxin production by Bacillus cereus

The natural antimicrobial compound carvacrol was investigated for its effec t on diarrheal toxin production by Bacillus cereus. Carvacrol (0-0.06 mg/ml ) reduced the viable count and the maximal specific growth rate (mu (max)) of B. cereus in BHI broth. The total amount of protein was not affected by carvacrol. However, a sharp decrease (80%) in diarrheal toxin production wa s observed in the presence of 0.06 mg/ml carvacrol. Carvacrol also inhibite d toxin production in soup, but approximately 50-fold higher concentrations were needed to achieve the same effect as in broth. From this study it can be concluded that carvacrol can be added to food products at doses below t he MIC value, thereby reducing the risk of toxin production by B. cereus an d increasing the safety of the products. (C) 2001 Elsevier Science B.V. All rights reserved.