Demonstration of Indicator Microorganisms on Surface of Vegetables on the Market in the United States and Mexico

Presence of indicator microorganisms of fecal pollution on the surface of vegetables sold in retail markets is demonstrated. Vegetables were obtained from local markets in the U.S.A. and Mexico. At least 1 of the indicators, among coliphages, fecal streptococci, total coliforms, and fecal coliforms, was detected in every sample tested. Relatively small amounts of indicators were recovered from the U.S.A. samples. Fecal streptococci showed significant correlations with all other indicators. However, some U.S.A. samples low in fecal streptococci were found to harbor certain levels of other indicators. Upon introduction of an indicator system to detect the fecal contamination of agriculture crops, it is recommended that multiple indicator microorganisms be measured.