Corn tortillas are a primary foodstuff in Mexico with nearly 12 million tons produced and consumed
annually. Federal health regulations control tortilla production and sale in Mexico, but most producers do
not fully implement them. No data are currently available on microbiological quality or presence of
pathogenic bacteria on tortillas produced in Mexico or other countries. Analyses of coliform bacteria (CB),
fecal coliforms (FC), Escherichia coli and Salmonella frequency were done on corn tortillas. Tortilla
samples were collected from small-scale producers called tortillerías. Two hundred samples (500 g) were
acquired at tortillerías in five municipalities in Hidalgo State, Mexico. CB were detected on 70% of
samples, FC on 40%, E. coli on 32% and Salmonella on 2%. In positive samples, CB concentration ranged
from 1 101 to 1 106 CFU/g, and FC and E. coli concentrations from 3 to 1100 MPN/g. CB, FC and E. coli
presence and concentration all correlated well with Salmonella presence in tortilla. The analysis of
KruskaleWalliseANOVA and median test of microbiological data showed that the microbiological quality
of tortillas samples did not differ between the different tortillerías. In addition, CB, FC and E. coli all
correlated well with Salmonella presence in tortilla.
This is the first report of microbiological quality of corn tortillas and Salmonella isolation from tortillas
in Mexico. Corn tortillas could be a potential source of enteropathogenic bacteria as Salmonella.