Modelling Cereulide production of Bacillus cereus under different temperature, pH, and water activity conditions

Cereulide production by Bacillus cereus constitutes a significant food safety hazard, yet its production kinetics under combined environmental stressors remain poorly quantified. This study aimed to develop quantitative models quantifying the effects of temperature (15-45 °C), pH (5.0-8.0), and water activity (0.945-0.996) on cereulide kinetics using the emetic strain F4810/72. The primary and secondary models were established to describe cereulide accumulation. The highest maximum concentration and production rate occurred at ambient temperatures, high water activity, and neutral-to-alkaline pH. Temperature was the dominant factor governing production rates. Notably, acidification to pH 5.0 extended the initial detection time by approximately 6 h relative to neutral pH, establishing a quantifiable early-warning window. Conversely, high water activity accelerated synthesis, while low water activity severely suppressed accumulation and extended the lag phase. These models provide a quantitative basis for risk assessment and confirm that temperature control, acidification, and moisture limitation represent potentially synergistic intervention strategies to mitigate cereulide risk in foods.