Frequency and Behavior of Salmonella and Escherichia coli on Whole and Sliced Jalapeno and Serrano Peppers

The frequencies of coliform bacteria (CB), thermotolerant coliforms (TC), Escherichia coli, and Salmonella were determined for jalapeno and serrano peppers. In addition, the behavior of four serotypes of Salmonella and three E. coli strains on whole and sliced jalapeno and serrano peppers as well as in blended sauce at 25 +/- 2 degrees C and 3 to 5 degrees C was investigated. Chili peppers were collected from markets in the city of Pachuca, Hidalgo, Mexico. CB, TC, E. coli, and Salmonella were detected on serrano peppers in 100, 90, 50, and 10% of the samples, and on jalapeno peppers in 100, 86, 32, and 12% of the samples. Concentrations of CB ranged from 3.8 to 7.9 log CFU per serrano sample and from 5.3 to 8.2 log CFU per jalapeno sample, whereas concentrations of TC and E. coli were between < 3 and 1,100 most probable number per serrano and jalapeno samples. On whole serrano and jalapeno peppers stored at 25 +/- 2 degrees C or 3 to 5 degrees C, no growth was observed for rifampin-resistant strains of Salmonella and E. coli. After 6 days at 25 +/- 2 degrees C, the tested Salmonella serotypes and E. coli strains had decreased from an initial inoculum level of 5 log CFU to 1 and 2.5 log on serrano and jalapeno peppers, respectively, and at 3 to 5 degrees C they decreased to approximately 1.8 and 1.2 log, respectively, on serrano and jalapeno. Both the Salmonella serotypes and E. coli grew on sliced chili peppers and in blended sauce; after 24 h at 25 +/- 2 degrees C, both bacteria types had grown to approximately 4 and 5 log CFU on pepper slices and in sauce, respectively. At 3 to 5 degrees C the bacterial growth was inhibited.