Purpose: The present work aimed at predicting (i) the prevalence and concentration of B. cereus during couscous preparation at consumer’s place, and (ii) the number of consumers exposed to 105cfu/g or more B. cereus in Algeria, due to couscous consumed on a weekly basis or during collective events.
Methods: The couscous semolina preparation was divided into three modules (i) the contamination at retail, (ii) the inactivation of B. cereus during couscous steaming and (iii) the growth during storage before serving. Each module was built using a combination of newly gathered data, literatures studies, predictive models and experts opinion information. Algeria was split into four regions: North, South, High plateau and Kabylie. The main differences between each region were the seasonal temperature and the consumption pattern. In absence of a dose-response model, a concentration of 105cfu/g of B. cereus was considered as a “risky” concentration.
Results: Per year, a total of 62 477 people (0.15% total population) and 41 602 people (0.10%) were estimated to be exposed to risky concentration due to weekly and collective consumption, respectively. The highest exposure came from for couscous semolina kept at ambient temperature, in south of Algeria during summer.
Significance: Cold storage and consumption within the first 12h after steaming are conditions which will limit the exposure to B. cereus in couscous.