Microbiological condition of ground meat retailed in Monterrey, Mexico

Eighty-eight samples of ground meat were randomly collected from retail sto res in the metropolitan area of Monterrey, Mexico, and were analyzed for mi crobial contamination. Methods were those recommended by the Mexican regula tion and/ or the U.S. Food and Drug Administration. Over 75% of the samples contained > 10(5) total mesophilic microorganisms per g, and over 40% had > 10(6) total coliforms per g. Fecal coliforms were present in most samples . Staphylococcus aureus was detected in 2.3% of the samples, Salmonella spp . in 11.4%, Listeria spp. in 62%, and L. monocytogenes in 16%. Escherichia coli was detected in 76% of samples, but none was serotype O157:H7. Shigell a spp. was not found in any sample. Fusarium spp. and Mucor spp. were detec ted in 3.4% of the samples, and low levels of yeast in 93%. The microbiolog ical quality of the ground meat analyzed was unsatisfactory, and the produc t could be an important cause of food poisoning.