Long-term Survival and Thermal Death Kinetics of Enterohemorrhagic Escherichia coli Serogroups O26, O103, O111 and O157 in Wheat Flour

摘要: ABSTRACT Wheat flour has been associated with outbreaks of enterohemorrhagic Escherichia coli (EHEC), but little is known on EHEC9s survival during storage and thermal processing. The objective this study was to determine long-term viability inactivation kinetics EHEC serogroups O26, O103, O111, O157. samples were inoculated a cocktail five strains single serogroup stored at 23 35°C. Inoculated heated 55, 60, 65, 70°C. Viability determined by plate counting. Decimal reduction time (D) first decimal (δ) values calculated log-linear Weibull models, respectively. At 23°C, counts declined gradually for 84 days tested positive from 280 days. resistance (D δ) ranged 7.5 8.2 3.1 5.3 days, respectively, there no significant differences among (P ≤ 0.05). 35°C, quantifiable day 7 detected after 49 Heating 55 65°C resulted in δ-value ranges 15.6 39.7 min 3.0 3.9 min, difference either. Z 12.6, 6.7, 10.2, 13.4°C O157, Thermal death better described using the model. Survival rates four remarkably similar. These findings indicated that all serovars remained viable least 9 months room temperature survived up 60 70°C wheat flour. IMPORTANCE Enterohemorrhagic (EHEC) Salmonella have recently caused several gastroenteritis recalls Because can cause illness very low doses scarce information regarding their ability survive heating flour, present undertaken assess O157 are relevant, as we report more than storage. In addition, results obtained suggest 30 or 2 35°C may be feasible strategies mitigate risk most