|109-1||Non-O157 Shiga-toxin–producing Escherichia coli and others pathogens in street vended Mexican fresh fruit beverages
|Autores:||Jorge Francisco Cerna Cortés (IPN - Instituto Politécnico Nacional) ; Wendy Vega Negrete (IPN - Instituto Politécnico Nacional) ; Monica A. Ortega Villegas (IPN - Instituto Politécnico Nacional) ; Jorge Alberto González-y-merchand (IPN - Instituto Politécnico Nacional) ; Teresa Estrada García (CINVESTAV-IPN - Centro de Investigaciones y de Estudios Avanzados del IPN) |
Introduction. Microbiological studies on street-vended foods have revealed high bacterial counts and a high incidence of foodborne bacterial pathogens in the food. In some cases, street-vended foods have been implicated in outbreaks of foodborne diseases. Therefore, the present study was initiated to evaluate the microbiological quality and the bacteriological safety of Mexican fresh fruit beverages collected in surrounding area of Our Lady of Guadalupe Shrine (the most visited religious center in the world).
Materials and methods. Fifty-six street vended Mexican fresh fruit beverages were collected and tested for common foodborne pathogens by standard methods. E. coli strains were analyzed by a multiplex PCR that detects the following pathogenic genes: heat-stable and heat-labile enterotoxins (st, lt) for enterotoxigenic E. coli (ETEC), intimin (eaeA) and bundle-forming pilus (bfpA) for enteropathogenic E. coli (EPEC), Shiga toxin 1 and 2 (stx1, stx2) and intimin (eaeA) for Shiga-toxin–producing E. coli (STEC), and invasion-associated loci (ial) for enteroinvasive E. coli (EIEC). Moreover, all E. coli strains were analyzed by a second multiplex PCR that detects 3 plasmid-borne virulence genes (aap, aggR, and aatA) from enteroaggregative E. coli (EAEC). Moreover, STEC strains were tested to determine if they expressed the O157 lipopolysaccharide antigen by using latex particle agglutination.
Results. Results showed that microbiological quality of tested samples was unsatisfactory because of large populations of aerobic mesophilic organisms (55%), total coliforms bacteria (11%) and fecal coliforms (20%). Foodborne pathogens were recovered from 6 of 56 (10.7%) samples, Aeromonas hydrophila, Citrobacter freundii, Salmonella group B and Non-O157 STEC were found.
Conclusion. The presence of foodborne pathogens in Mexican fresh fruit beverages may cause illness to 20 million pilgrims that visit the Shrine of Our Lady of Guadalupe each year.
Palavras-chave: street-vended foods,, Non-O157 STEC, Mexican fresh fruit beverages, foodborne diseases