Study Reveals Bacillus cereus as Underrecognized Risk to Food Safety in Africa
A new review published in Springer Nature’s Discover Public Health has highlighted the prevalence of Bacillus cereus in African food systems, particularly in cereal-based foods, dairy products, and ready-to-eat (RTE) street foods, as well as significant gaps in surveillance for the foodborne pathogen across the continent.
Conducted by researchers from the Mali National Institute of Public Health and two universities in Benin (the University of Parakou and the University of Abomey-Calavi), the review synthesized available evidence on B. cereus contamination, toxin gene diversity, and antimicrobial resistance (AMR) in African food systems from January 2000–October 2025.
Despite covering a 25-year period, only ten studies met the researchers' eligibility criteria, highlighting a scarcity of data across Africa's 54 countries. The included studies represented ten countries, primarily in West and East Africa.
High Rates of B. cereus Contamination in African Foods
The reviewed studies reported B. cereus contamination in food at rates ranging from approximately 15 percent to more than 70 percent, depending on food type and detection method.
Some of the highest contamination rates were reported in cereal-based foods in Nigeria (71 percent), milk and dairy products in Ghana (68 percent), fermented milk in Tanzania (55 percent), and street foods in Côte d'Ivoire (52 percent). In Burkina Faso, B. cereus was detected in 42 percent of tested infant cereals, raising concerns about exposure among vulnerable populations.
The researchers highlighted inadequate temperature control, limited refrigeration infrastructure, and improper storage of cooked foods as important factors contributing to the proliferation of B. cereus. The pathogen's ability to form heat-resistant spores also allows it to survive certain food preparation processes.
Toxin and Antimicrobial Resistance Genes Identified
The review also identified widespread detection of toxin-associated genes among B. cereus isolates (i.e., nhe, hbl, and cytK), which are associated with diarrheal illness. The nhe gene cluster was detected in 70–100 percent of isolates in the reviewed evidence. Meanwhile, the ces gene cluster, associated with production of the emetic toxin cereulide, was less frequently detected but was present in some isolates.
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Additionally, resistance to β-lactam antibiotics, including penicillin and ampicillin, was consistently reported. Multidrug resistance was reported in 8–22 percent of isolates from Ghana, Ethiopia, and South Africa.
Researchers Call for Stronger Foodborne Pathogen Surveillance
The researchers emphasized that fragmented surveillance systems, limited laboratory capacity, and insufficient coordination between food safety and public health authorities likely contribute to the underrecognition of B. cereus foodborne illness in Africa.
To address these gaps, the authors recommended strengthening laboratory capabilities, including polymerase chain reaction (PCR) testing and whole-genome sequencing (WGS); standardizing surveillance protocols; expanding food safety education for informal food vendors; and implementing systematic AMR monitoring.
The researchers also recommended integrating B. cereus surveillance into existing foodborne disease networks and aligning these efforts with the African Union’s Food Safety Strategy 2022–2036 and One Health initiatives.
