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

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 center dot 8, 54 center dot 3, 8 center dot 9 and 8 center dot 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 center dot 6x102 to 8 center dot 5x107 CFU ml1, and the limits for FC and E.coli were <3 to 1100 MPN ml1 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 center dot 5% (C3); Salmonella, 5% (A1, A2, B2), 7 center dot 5% (C2), 10% (C1), 12 center dot 5% (B1) and 15% (C3).