2017 ASHS Annual Conference

Improving food safety and reducing foodborne illnesses are USDA-NIFA high priority areas. Ongoing research at the University of Maryland Eastern Shore (UMES) in collaboration with USDA-ARS, US-FDA, MD, Maryland Department of Environment, and many collaborating universities focuses on addressing avenues leading to fresh produce and seafood contamination with pathogenic microorganisms such as E. coli 0157:H7, Salmonella, Staphylococcus and Vibrio. Irrigation water, insects, manure amendments to cropland, runoff water, farm machinery and practices, and bioaerosol generated from farm operations are potential avenues leading to fresh produce contamination. Our main objective is to minimize microbial contamination of fresh produce at the farm level. Our bioaerosol studies revealed that while generic E. coli traveled up to 50 feet, Staphylococcus traveled to more than 600 feet from the litter-handling site and; therefore, Staphylococcus could be used as a marker in bioaerosol studies. Our rain simulation studies, where soils were amended with poultry litter, poultry compost, and dairy and swine manure, showed that poultry manure enhanced growth of bacteria more than any other manure. Similar findings were found in our field studies where soil was amended with various manure types and inoculated with non-pathogenic strains of generic E. coli and attenuated E. coli 0157:H7. An irrigation study where field-grown tomatoes were inoculated 10 days before harvest with bovine manure examined the persistence of generic E. coli and total coliforms; bacterial populations fluctuated in response to weather events within the 10-day sampling period. Addition studies are also being conducted to gain quantitative insights about pathogen survival and persistence in field production of fresh produce.