Assessment of the Survival of Microbial Pathogens in the Environment

Abstract

The studies presented here evaluate the survival of different types of pathogens in a variety of environments. The study Appendix A focuses on the presence of enteric bacteria in reusable shopping bags. We demonstrated that ninety-seven percent of individuals surveyed never washed their reusable shopping bags and that this lack of washing can lead to the buildup of potentially harmful bacteria such as Salmonella spp. The hand-washing of the bags was shown to reduce seeded organisms to below detectable limits. Appendix B examines the survival of Bacillus altrophaeus endospores during household laundering. It was demonstrated that detergent alone didn't significantly reduce the number of viable endospores or their spread to other garments and that bleach is necessary to significantly reduce the number of viable endospores and their spread. Risks for infection were significantly lower when bleach was used during laundering. Appendix C details the survival of Ascaris ova in biosolid-amended Brazito sandy loam and clay loam. Survival of Ascaris ova was significantly higher in clay soil and ova inactivation increased with increasing temperature. The risk for Ascaris infection from consuming raw lettuce grown on such soils was calculated and it was found that annual risks for infection decreased significantly with time after harvest.