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The potential presence of spore-forming bacteria related to the Bacillus cereus group in Mexican chili powder elaborated from Capsicum annuum L. is of commercial and clinical interest, because chili powder is an essential spice in the Mexican diet and in diets around the globe. To facilitate detection and isolation of members of this group of spore-forming bacteria from Mexican chili powder samples, we identified colonies that grew on agar medium selective for Bacillus cereus sensu lato, supplemented with polymyxin B (10 µg/mL) and ampicillin (10 to 100 µg/mL). The presumptive B. cereus ( s.l. ) isolates were tested using a tRNA Cys -PCR-based approach and the results identified species related phylogenetically to B. cereus , B. thuringiensis, and B. toyonensis . Their toxigenic potential was assessed by serological tests to detect enterotoxins (Nhe and Hbl) and by PCR targeting the hemolysin BL ( hbl ) component C ( hblC ) and non-hemolytic enterotoxin component A ( nheA ). The antibiotic profiles of the isolates showed a high resistance to β-lactams (100% of the isolates), trimethoprim-sulfamethoxazole (100%), tetracycline (90%), erythromycin (77%), clindamycin (74%), and chloramphenicol (42%). Our results indicate the presence of B. cereus s.l. with toxigenic characteristics in Mexican chili powder. Because of the potential for these organisms to cause disease through their production of various toxins, and resistance to antibiotics, we recommend that a microbiological risk assessment must be considered in the Mexican regulatory requirements.

American foulbrood (AFB) caused by Paenibacillus larvae is the most destructive honeybee bacterial disease and its dissemination via commercial bee pollen is an important mechanism for the spread of this bacterium. Because Mexico imports bee pollen from several countries, we developed a tRNA Cys -PCR strategy and complemented that strategy with MALDI-TOF MS and amplicon-16S rRNA gene analysis to evaluate the presence of P. larvae in pollen samples. P. larvae was not detected when the tRNA Cys -PCR approach was applied to spore-forming bacterial colonies obtained from three different locations and this result was validated by bacterial identification via MALDI-TOF MS. The genera identified in the latter analysis were Bacillus (fourteen species) and Paenibacillus (six) species. However, amplicon-16S rRNA gene analysis for taxonomic composition revealed a low presence of Paenibacillaceae with 0.3 to 16.2% of relative abundance in the commercial pollen samples analyzed. Within this family, P. larvae accounted for 0.01% of the bacterial species present in one sample. Our results indicate that the tRNA Cys -PCR, combined with other molecular tools, will be a useful approach for identifying P. larvae in pollen samples and will assist in controlling the spread of the pathogen.

In the article mentioned above an author's name was misspelled.