A review: Three-gate framework for strain-level safety assessment of Bacillus cereus in food systems

Bacillus cereus occupies an unusual position in food systems because individual strains may cause emetic intoxication, diarrhoeal toxicoinfection and spoilage, whereas selected strains have been investigated for agricultural, feed and food-biotechnology functions. Species identity alone is therefore an inadequate basis for safety decisions. This review synthesises current evidence and proposes a three-gate framework that converts strain data into use-specific actions. Gate 1 provides an early stop for definitive genomic hazards and transferable antimicrobial-resistance (AMR) determinants. Gate 2 uses matrix-specific liquid chromatography-tandem mass spectrometry (LC-MS/MS), enterotoxin assays and epithelial-cell activity to place toxin output into transparent decision tiers. Gate 3 converts the remaining hazard into an exposure decision using dose, product format, route, persistence, edible-tissue transfer and vulnerable-consumer criteria. In practice, the sequence yields auditable outcomes-exclude, restrict, conditionally authorise or permit controlled cell-free use-while identifying the missing test or control needed to move a candidate forward. Evidence-anchored cases show that the framework prevents a beneficial phenotype from substituting for toxin testing, avoids treating a single negative broth result as proof of safety, and prioritises expensive functional studies only after genomic triage. The framework is therefore intended as a dossier-structuring and risk-management tool for regulators, feed businesses and food manufacturers, rather than as a new universal toxicological threshold.