Effect of Temperature on Survival of Escherichia coli O157:H7 and Listeria monocytogenes in Livestock Manure Compost

Animal manure compost is a commonly used fertilizer in organic vegetable and fruit production in Korea. However, livestock manure compost produced from animal feces can contain a lot of the non-pathogenic and pathogenic bacteria. Of particular concern are bacteria causing human food-borne illness such as Escherichia coli O157:H7 and Listeria monocytogenes. The objective of this study was to investigate effect of temperature on survival of E. coli O157:H7 and L. monocytogenes in livestock manure compost. Commercial livestock manure compost (manure 60%, sawdust 40%) was inoculated with E. coli O157:H7 and L. monocytogenes. Compost was incubated at four different temperatures (10, 25, 35, and 55℃) for 20 weeks. Samples were taken every week during incubation depending on the given conditions. E. coli O157:H7 persisted for up to 1 day in livestock manure compost at 55℃, over 140 days at 10℃, 140 days at 25℃, and 120 days at 35℃, respectively. L. monocytogenes persisted for up to 1 day in livestock manure compost at 55℃ and 140 days at 10℃, 70 days at 25℃, and 40 days at 35℃, respectively. The results indicated that E. coli O157:H7 and L. monocytogenes persisted longer under low temperature condition. E. coli O157:H7 survived longer than L. monocytogenes at three different temperatures (10, 25, and 35℃). The results are being used to develop guidelines on the management of manure to reduce the risks of E. coli O157:H7 and L. monocytogenes transmission to foods produced in the presence of animal waste.