Fate of Salmonella enterica and Enterohemorrhagic Escherichia coli cells, Artificially Internalized into Vegetable Seeds during Germination.

This study was undertaken to observe the physiological behavior of Salmonella enterica and enterohemorrhagic Escherichia coli (EHEC) cells, artificially internalized into vegetable seeds during the germination process. Surface-decontaminated seeds of alfalfa, fenugreek, lettuce, and tomato were vacuum-infiltrated with four individual strains of Salmonella or EHEC. Contaminated seeds were germinated at 25°C for 9 days and different sprout/seedling tissues were microbiologically analyzed every other day. Internalization of Salmonella and EHEC cells into vegetable seeds was confirmed by the absence of pathogens in seed-rinsing water and presence of pathogens in seed homogenates after post-internalization seed surface decontamination. Results show that 317 (62%) and 343 (67%) out of the 512 collected sprout/seedling tissue samples were positive for Salmonella and EHEC, respectively. Average Salmonella populations were significantly higher (p<0.05) than the EHEC populations. Significantly higher Salmonella populations were recovered from the cotyledon and seed coat tissues, followed by the root tissues, but the mean EHEC populations from all sampled tissue sections were statistically similar, except pre-germinated seeds. Three Salmonella, and two EHEC, strains had significantly higher cell populations on sprout/seedling tissues than other strains used in the study. Salmonella and EHEC populations from fenugreek and alfalfa tissues were significantly higher than those from toma...
Source: Applied and Environmental Microbiology - Category: Microbiology Authors: Tags: Appl Environ Microbiol Source Type: research