Presence of indicator bacteria, diarrhoeagenic Escherichia coli pathotypes and Salmonella in fresh carrot juice from Mexican restaurants

Abstract

Coliform bacteria (CB), faecal coliforms (FC), Escherichia coli, diarrhoeagenic E. coli pathotypes (DEP) and Salmonella frequencies were determined for fresh carrot juice from restaurants in Pachuca city, Mexico. Two hundred and eighty carrot juice samples were purchased in three types of restaurants: (A), national chain restaurants; (B), local restaurants; and (C), very small restaurants. Two restaurants for each A and B, and three for C, were included. Forty juice samples were purchased at each restaurant. All tested juice samples had poor microbiological quality. Of these samples, 100, 96·8, 54·3, 8·9 and 8·6% had CB, FC, E. coli, DEP and Salmonella, respectively. CB were present in all juice samples regardless of source, with limits ranging from 3·6 × 102 to 8·5 × 107 CFU ml−1, and the limits for FC and E. coli were <3 to 1100 MPN ml−1 and <3 to 460 MPN, respectively. DEP and Salmonella were isolated from samples from all the restaurants at levels of 5% or above: DEP, 5% (A1, B2), 10% (A2, B1, C1, C2) and 12·5% (C3); Salmonella, 5% (A1, A2, B2), 7·5% (C2), 10% (C1), 12·5% (B1) and 15% (C3). Significance and Impact of the Study This is the first report of microbiological quality and Salmonella, enteroinvasive E. coli (EIEC), enterotoxigenic E. coli (ETEC) and Shiga toxin‐producing E. coli (STEC) isolation from fresh carrot juice in Mexico. Fresh carrot juice from restaurants could be an important factor contributing to the endemicity of EIEC‐, ETEC‐ and STEC‐ and Salmonella‐caused gastroenteritis in Mexico.

Presence of Shiga Toxin–Producing Escherichia coli, Enteroinvasive E. coli, Enteropathogenic E. coli, and Enterotoxigenic E. coli on Tomatoes from Public Markets in Mexico

“…Similar results showing the lack of 0157 and H7 antigens in STEC strains isolated in Mexico have been reported (9). STEC strains have been identified from raw foods in Mexico such as vegetable salads (3) and carrot juice (27).…”

“…These pathogens usually are transmitted by contaminated food. The ETEC pathotype has been isolated from raw vegetable salads (3) and carrot juice (27). EPEC is a leading cause of diarrhea in developed countries (9,28).…”

Presence and Correlation of Some Enteric Indicator Bacteria, Diarrheagenic Escherichia coli Pathotypes, and Salmonella Serotypes in Alfalfa Sprouts from Local Retail Markets in Pachuca, Mexico

“…For the STEC, only the stx2 locus was detected in one strain, the stx\ locus was detected in three strains, and both stx\ and stx2 were detected in one strain ( Table 2). STEC strains have been identified from raw foods in Mexico, including vegetable salads (5) and carrot juice (46). The pathogenesis of STEC is linked to different virulence factors, such as Shiga toxins (the products of stxi and stx2) (35).…”

Salmonella and Tomatoes

“…Results showed that 99% of the analyzed RTE salads were contaminated with fecal coliforms; 85% harbored E. coli and 7% diarrhoeagenic E. coli pathotypes (DEPs) . Moreover, 96.8% of analyzed juices were contaminated with fecal coliforms, 53.6% harbored E. coli, 8.9% DEPs, and 8.6% were positives for Salmonella (Torres-Vitela et al, 2013). The fact that almost all salads and juices samples were contaminated with fecal matter regardless of the status of hygiene of the restaurants, it may be because most vegetables consumed in Pachuca-City are grown in the Mezquital Valley.…”

“…The fact that almost all salads and juices samples were contaminated with fecal matter regardless of the status of hygiene of the restaurants, it may be because most vegetables consumed in Pachuca-City are grown in the Mezquital Valley. Thus, contamination most likely originated from irrigation water rather than from poor sanitation practices at the restaurants (Torres-Vitela et al, 2013).…”