A systematic review and meta-analysis of the prevalence of Bacillus cereus in foods

Bacillus cereus is a ubiquitous and highly resistant food poisoning bacterium that is an important food safety concern. It can contaminate a variety of foods throughout the world. In this systematic review and meta-analysis, a complete search was conducted on the prevalence of B. cereus, worldwide. Between 1990 and 2020, a total of 6035 articles were collected from the databases. By applying explicit criteria, the number of 98 studies was included in this study. The overall prevalence of B. cereus obtained in this study was 23.746% with a confidence interval of (95%) 22.979–24.513. However, the prevalence of B. cereus varied according to food type, identification method and continents. Our findings showed that the highest prevalence of B. cereus among eight groups of foods belonged to the cereals and beans, with 41.489% and 44.901%, respectively. Its prevalence was also high in vegetables (37.279%) and dairy products (36.385%). The detection methods used also affected reporting the prevalence of B. cereus. In general, the molecular tests such as PCR, reported twice the prevalence compared to other methods. The prevalence of B. cereus was also the highest in the Americas and lowest in Australia. However, with some exceptions, the prevalence of B. cereus in developing countries was significantly higher than in the developed countries. This study indicates that although the prevalence of B. cereus is generally high, depending on the type of food, the method of bacterial detection and also geographically, its prevalence can be quite different. The high prevalence of B. cereus in different food types can be attributed to B. cereus origin, the soil and non-compliance with hygienic protocols from farm to the fork, so it is still possible to prevent food contamination to this bacterium by observing hygienic principles. In addition, it is recommended to use molecular detection methods along with the Culture/Biochemical methods to obtain a more accurate prevalence of food contamination to B. cereus.