Fecal coliforms are defined as coliforms that ferment lactose with gas production within 48 hours at 45ºC. Escherichia coli and some strains of Enterobacter and Klebsiella show these same characteristics. However, only the presence of E. coli can indicate fecal contamination of foods, because it is abundantly found in the intestinal tract of all warm-blooded animals, including the humans, and it is not usually found in others niches. The classic denomination of fecal coliforms was changed to coliforms at 45ºC in the Resolution nº 12/2001 of the National Surveillance Agency of Brazil. The objectives of this study were to analyse the presence of E. coli among the coliforms at 45ºC and to compare the methods of Most Probable Number Method (MPN) and Petrifilm EC in their efficiency to detect E. coli in Minas cheese, sausage, fresh vegetables and corn flower samples. Petrifilm EC was more accurate method than MNP method, which presented false negative results or underestimation of E. coli. In conclusion, Petrifilm EC was an efficient and practical method to detect E. coli. Therefore, it may be alternatively used for enumeration of total coliforms and E. coli in foods.
total coliforms; E. coli; Petrifilm; MNP method
