Incidence, toxin gene profile, antibiotic resistance and antibacterial activity of Allium parvum and Allium cepa extracts on Bacillus cereus isolated from fermented millet-based food

Bacillus cereus is a major food poisoning pathogen that generates spores and biofilms, allowing it to survive in varied food systems. This study revealed the incidence, virulence toxin gene profiling, multi-drug resistance of B. cereus from traditional fermented millet-based porridge foods. The antibacterial activity of onion bulbs (Allium parvum and Allium cepa) against B. cereus isolates was also studied. Of 85 millet-based porridge samples collected from 17 locations, 71 samples (83.5%) were contaminated with B. cereus. Toxin gene profiling study revealed that, 31 B. cereus strains isolated from millet-based porridge samples were reported to have hbl (hblA-35.48%, hblC-51.61% and hblD-45.16%), nhe (nheA-48.38%, nheB-45.16% and nheC-41.93%), cytK-58.06%, entFM-70.96% and ces-6.45%. The antibacterial activity of A. parvum showed a higher range of zone of inhibition (ZOI), 13.66 ± 0.57 mm to 21.00 ± 1.00 mm due to the presence of bioactive compounds identified by FTIR and UPLC-MS/MS. In summary, our study confirmed the detection of B. cereus toxin in fermented millet-based porridge and prospects for its effective control by A. parvum extracts.