Retail Risk Assessment and Lethality of Listeria monocytogenes and E. coli O157 in Naturally Fermented Sauerkraut
The interest in fermenting foods at retail and food service levels is increasing. Foodborne pathogens such as E. coli O157:H7 and Listeria monocytogenes, however, have been implicated in foodborne illness in several fermented and acidic foods. This study evaluated and validated the lethality of potentially acid-tolerant pathogens E. coli O157 and L. monocytogenes in sauerkraut that was made using traditional fermentation techniques. Fresh cabbage juice prepared with 2.5% salt was inoculated separately with a 5-strain mixture of E. coli O157 and a 5-strain mixture of L. monocytogenes and then was allowed to ferment at 25 °C. The pH decreased at a steady rate for the first 7 days and remained relatively stable thereafter. There was a significant decrease in E. coli O157 from Day 1 to Day 7 (p < .05) and a significant decrease in L. monocytogenes count from Day 2 to Day 7 (p < .05) with a 5-log reduction for both pathogens at Day 7 and no pathogens detected after Day 9. The data indicate that fermentation of cabbage at ambient temperature is lethal to the survival of E. coli O157 and L. monocytogenes. This study can be used to support the safety of sauerkraut fermentations in retail and food service operations.
Speaker / Author:
Sujan Acharya, Nutrition, Dietetics, and Food Sciences Department, Utah State University
Brian A. Nummer, PhD, Nutrition, Dietetics, and Food Sciences Department, Utah State University