Microbial quality and prevalence of foodborne pathogens of cheeses commercialized at different retail points in Mexico

Abstract

Microbial quality and the prevalence of foodborne pathogens (E. coli 0157:H7, Salmonella spp., Listeria monocytogenes and Campylobacter jejuni) of cheeses sold at three retail points (supermarkets [SM], street markets [ST], and convenience grocery stores [CGS]) in Chihuahua, Mexico, were evaluated (n=90). The most commonly found cheeses in the retail points were Chihuahua (60%) and Ranchero (28.8%). According to Mexican standards, three SM, two CGS, and none of the ST cheeses complied with the regulations. Two cheeses (cheddar and Ranchero) from SM (2.22%) were positive for L. monocytogenes. Eight cheeses (8.88%) were positive for Salmonella spp. (5 from ST and 3 from CGS). E.coli 0157:H7 and Campylobacter jejuni were negative in all samples. On the Ranchero cheese, total coliforms (TC), faecal coliforms (FC), and yeast and moulds (Y&M) showed no significant differences (P > 0.05) among retail points. Nevertheless, in Chihuahua cheese, the numbers of total coliforms, faecal coliforms, and yeast and moulds were statistically different (P < 0.05) among retail points. PSM Chihuahua cheese had the lowest numbers of total (0.99 ± 1.0 Log 10 CFU/g) and faecal coliforms (166 ± 154 Log 10 CFU/g). CGS cheeses had the lowest counts in terms of yeast and moulds (3.1 ± 2.2 Log 10 CFU/g). The results revealed that most cheeses, regardless of the retail point, did not conform to Mexican standards. The number of total and faecal coliforms indicates either flaws during the production and commercialization processes or the ill-handling of raw materials.

Artisanal Fresco cheese from Sonora: Physicochemical composition, microbial quality, and bacterial characterization by high‐throughput sequencing

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Antibacterial mechanism of apple phloretin on physiological and morphological properties of Listeria monocytogenes

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Effect of water activity and storage of tahini on the viability of stressed Salmonella serovars

“…The undercooked meat and meat products, particularly poultry products have been known as a major source of Salmonella serotypes; however, other food products such as fresh produce, dairy products, and low a w foods have been found to be contaminated with different Salmonella spp. (Beuchat et al, 2013;Chávez-Martínez et al, 2019;Cruz et al, 2019;Cunha-Neto et al, 2019;Mendonça et al, 2019). Salmonella can be eliminated from foods by pasteurization of high a w foods such as liquid milk or juices (Beuchat et al, 2013) or using the microwave processing of low a w foods such as infant milk (Portela et al, 2019), which indicates the susceptibility of Salmonella to heat.…”