Enteric pathogens in Mexican sauces of popular restaurants in Guadalajara, Mexico, and Houston, Texas

Background: The transmission of traveler's diarrhea is primarily foodborne. Objective: To examine the level of microbial contamination of tabletop sauces found in Mexican-style restaurants. Design: Cross-sectional study of Mexican sauces. Setting: Mexican restaurants in Guadalajara, Mexico, and Houston, Texas, during the summer of 1998. Measurements: 71 sauces from Guadalajara and 25 sauces from Houston were examined. The number of sauces contaminated with Escherichia coli, the median number of E. coli colonies per gram of sauce, and enteropathogens were identified. Results: 47 of 71 sauces from Guadalajara were contaminated with E. coli versus 10 of 25 sauces from Houston (P = 0.03); the median number of E. coli colonies per gram of sauce was 1000 in the Guadalajara sauces versus 0.0 in the Houston sauces (P = 0.007). Among sauces from Guadalajara tested for diarrheogenic E. coli, 4 of 43 sauces contained enterotoxigenic E. coli and 14 of 32 contained enteroaggregative E. coli. Conclusions: Contamination with E. coli was common in samples of Mexican tabletop sauces from Guadalajara restaurants. These sauces commonly contained enteric pathogens.