Survival of Salmonella enterica and Listeria monocytogenes in Chicken and Pig Manure Compost

Livestock manure is a valuable source of nutrients and organic matter for plant. Thus, livestock manure compost is commonly used fertilizer in organic vegetable and fruit production in many countries. However, contaminated or inadequate manure compost can give negative effect to soil microorganisms. This study was conducted to investigate the survival difference of Salmonella enterica and Listeria monocytogenes in chicken and pig manure compost under the selected environmental conditions. Commercially available manure compost (pig, chicken) was inoculated with S. enterica and L. monocytogenes. Manure compost was incubated at $25^{\circ}C$ and consistent moisture content. Samples had been collected during 200 days depending on the given conditions. S. enterica survived for 130 days in pig manure compost and over 200 days in chicken manure compost, respectively. L. monocytogenes persisted for 120 days in pig manure compost and over 200 days in chicken manure compost, respectively. It is noted that the number of S. enterica and L. monocytogenes gradually decreased over time. The results indicate that S. enterica survived longer than L. monocytogenes in manure compost at $25^{\circ}C$ . S. enterica and L. monocytogenes survived longer in chicken manure compost than in pig manure compost. Increased knowledge of pathogen behavior in agricultural environments is a valuable part of future work on improving risk evaluations and, in a longer perspective, in providing data for guidelines regarding safe handling of pathogen-contaminated manure compost and soil.