The influence of nisin on the thermal resistance of Bacillus cereus

Abstract

Decimal reduction times (D-values) at cooking and autoclaving temperatures (80 to 120°C) of spores of Bacillus cereus ATCC 1479-8 in rice and milk (13% wt/vol) supplemented with nisin (25 μg/ml) were evaluated. The mean D-values at 97.8°C in cooked white rice, phosphate buffer (pH 7.0), and rice water (pH 6.7) were 3.62, 1.99, and 1.34 min, respectively. From 80 to 100°C, the mean reduction in D-values due to the addition of nisin to milk was 40%. The D-value at 110°C was ∼0.86 min for milk (control) and milk with nisin. The z-values ranged from 7.32°C (phosphate buffer) to 10.37°C (milk control).