Behavior of enteroaggregative Escherichia coli, non-0157-shiga toxin-producing E. coli, enteroinvasive E. coli, enteropathogenic E. coli and enterotoxigenic E. coli strains on mung bean seeds and sprout

The behavior of enteroaggregative Escherichia coli (EAEC), non-0157 shiga toxin-producing E. coli (non-0157-STEC), enteroinvasive E. coli (EIEC), enterotoxigenic E. coli (ETEC) and enteropathogenic E. coli (EPEC) on mung bean seeds at 25 plus or minus 2 degree C and during germination and sprouting of mung bean seeds at 20 plus or minus 2 degree and 30 plus or minus 2 degree C and on mung bean sprouts at 3 plus or minus 2 degree C was determined. When mung bean seeds were inoculated with EAEC, non-0157 STEC EIEC, EPEC or ETEC strains, all these diarrheagenic E. coli pathotypes (DEPs) survived at least 90 days on mung bean seeds at 25 plus or minus 2 degree C. All DEPs grew during germination and sprouting of seeds, reaching counts of approximately 5 Log and 7 Log CFU/g after 2 days at 20 plus or minus 2 degree and 30 plus or minus 2 degree C, respectively. However, when the sprouts were inoculated after 1 day of seeds germination and stored at 20 plus or minus 2 degree or 30 plus or minus 2 degree C, no growth was observed for any DEPs during sprouting at 20 plus or minus 2 degree C per 9 d; however, a significant increase in the concentration of DEPs of approximately 0.7 log CFU/g was observed during sprouting at 30 plus or minus 2 degree C after 1 day of sprout contamination. Refrigeration reduced the number of viable DEPs strains on sprouts after 10 days in storage; nevertheless, these decreases have no practical significance in the safety of the sprouts.