Effect of Temperature on Survival of Salmonella enterica and Staphylococcus aureus in Livestock Manure Compost

Manures contain a variety of pathogenic microorganisms that pose a risk to human or animal. On-farm contaminations through contaminated manure were considered likely sources of the pathogen for several outbreak. Pathogenic microorganisms may survive in low numbers during the composting process and subsequently regrow to high levels under favorable conditions. The objective of this study was to investigate effect of temperature on survival of Salmonella enterica and Staphylococcus aureus in livestock manure compost. Commercial livestock manure compost (manure 60%, sawdust 40%) was inoculated with S. enterica and S. aureus. 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. S. enterica persisted for up to 1 day in livestock manure compost at 55℃, over 140 days at 10℃, 140 days at 25℃, and 70 days at 35℃, respectively. S. aureus persisted for up to 1 day in livestock manure compost at 55℃ and 90 days at 10℃, 70 days at 25℃, and 40 days at 35℃, respectively. The results indicate that S. enterica and S. aureus persisted longer under low temperature condition. S. enterica survived longer than S. aureus at three different temperatures (10, 25, and 35℃). This study will provide useful and practical guidelines to applicators of soil in deciding appropriate handling and time frames for land application of livestock manure compost for sustainable agriculture. Results from these studies provide useful information in identifying manure handling practices to reduce the risk of S. enterica and S. aureus transmission to fresh produce.