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 tRNACys-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.

Efecto de la fuente de inóculo en la digestión anaerobia de vinazas de mezcal a diferentes proporciones sustrato-inóculo

Vinasses are a very harmful residue of the alcohol distillation, their discharge into soil and water can cause negative environmental impacts if the appropriate treatments do not take place. Anaerobic digestion has shown to be the best technological and economical method to treat this residue, thus bioenergy can be generated as by-product of this process. Nevertheless, the slow adaptation of the microbial consortium in inoculum (activated sludge) to the substrate (mezcal vinasses) is very important to enhance the efficiency of the biogas and methane production, as well as organic matter removal. In this work, the adaptation process of the anaerobic digestion of mezcal vinasses was carried out in a 30-day period. Inoculum (activates sludge) and vinasses were mixed initially at the ratio 7:3. The feeding steps were done every seven days replacing 30 % of the total volume with new vinasses. Biogas was quantified and qualified. Biogas production reached 217 L/kgVSvinasses generating a daily methane content between 50 and 55 % by the end of the adaptation period. The organic matter removal efficiency was almost seven times higher at the end of the adaptation, in comparison to the beginning. This suggests that a slow adaptation process enhance the organic matter removal and eventually other pollutants in vinasses. When comparing this results with the literature, biogas and methane production were similar, nevertheless the anaerobic digestion could be optimized, in order to increase the methane content in biogas and the removal rate of organic matter. Palabras clave: biogás, demanda química de oxígeno, FOS/TAC, metano RESUMEN Las vinazas son un residuo proveniente de la destilación de alcohol, su descarga en suelos y aguas puede causar impactos ambientales negativos si no se realizan los tratamientos adecuados antes de considerar su descarga. La digestión anaerobia ha demostrado ser un método con ventajas tecnológicas y económicas para tratar este residuo y generar bioenergía al mismo tiempo. Sin embargo, una lenta adaptación del consorcio microbiano contenido en el inóculo (lodo activado) al sustrato (vinazas

Chili powder is the most frequently consumed spice in Mexican diets. Thus, the dissemination of microorganisms associated with chili powder derived from Capsicum annuum L. is significant during microbial quality analysis, with special attention on detection of potential pathogens. The results presented here describe the initial characterization of bacterial community structure in commercial chili powder samples. Our results demonstrate that, within the domain Bacteria, the most abundant family was Bacillaceae, with a relative abundance of 99% in 71.4% of chili powder samples, while 28.6% of samples showed an average relative abundance of 60% for the Enterobacteriaceae family. Bacterial load for aerobic mesophilic bacteria (AMB) ranged from 104 to 106 cfu/g, while for sporulated mesophilic bacteria (SMB), the count ranged from 102 to 105 cfu/g. Bacillus cereus sensu lato (s.l.) was observed at ca. ˂600 cfu/g, while the count for Enterobacteriaceae ranged from 103 to 106 cfu/g, Escherichia coli and Salmonella were not detected. Fungal and yeast counts ranged from 102 to 105 cfu/g. Further analysis of the opportunistic pathogens isolated, such as B. cereus s.l. and Kosakonia cowanii, using antibiotic-resistance profiles and toxinogenic characteristics, revealed the presence of extended-spectrum β-lactamases (ESBLs) and Metallo-β-lactamases (MBLs) in these organisms. These results extend our knowledge of bacterial diversity and the presence of opportunistic pathogens associated with Mexican chili powder and highlight the potential health risks posed by its use through the spread of antibiotic-resistance and the production of various toxins. Our findings may be useful in developing procedures for microbial control during chili powder production.

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