Behavior of non-O157 Shiga toxin-producing Escherichia coli, enteroinvasive E. Coli, enteropathogenic E. Coli, and enterotoxigenic E. coli strains on alfalfa sprouts

Data about the behavior of non-O157 Shiga toxin-producing Escherichia coli (non-O157 STEC), enteroinvasive E. coli (EIEC), enterotoxigenic E. coli (ETEC), and enteropathogenic E. coli (EPEC) on seeds and alfalfa sprouts are not available. The behavior of STEC, EIEC, ETEC, and EPEC was determined during germination and sprouting of alfalfa seeds at 20 Zapotitlán 2°C and 30 Zapotitlán 2°C and on alfalfa sprouts at 3 Zapotitlán 2°C. When alfalfa seeds were inoculated with STEC, EIEC, ETEC, or EPEC strains, all these diarrheagenic E. coli pathotypes (DEPs) grew during germination and sprouting of seeds, reaching counts of approximately 5 and 6 log CFU/g after 1 day at 20 Zapotitlán 2°C and 30 Zapotitlán 2°C, respectively. However, when the sprouts were inoculated after 1 day of seed germination and stored at 20Zapotitlán2°C or 30Zapotitlán2°C, no growth was observed for any DEP during sprouting at 20Zapotitlán2°C or 30 Zapotitlán 2°C for 9 days. Refrigeration reduced significantly (P < 0.0.5) the number of viable DEPs on sprouts after 20 days in storage; nevertheless, these decreases have no practical significance for the safety of the sprouts. Copyright Zapotitlán International Association for Food Protection