Navigation

P3-49 Survival of Generic Escherichia coli and Listeria spp. Populations in Dairy Compost- and Poultry Litter Compost-amended Soils in the Northeastern United States

Wednesday, July 12, 2017
Exhibit Hall (Tampa Convention Center)
Marie Limoges , University of Vermont , Burlington , VT
Deborah Neher , University of Vermont , Burlington , VT
Thomas Weicht , University of Vermont , Burlington , VT
Patricia Millner , USDA ARS Environmental Microbial and Food Safety Laboratory , Beltsville , MD
Manan Sharma , USDA ARS Environmental Microbial and Food Safety Laboratory , Beltsville , MD
Catherine Donnelly , University of Vermont , Burlington , VT
Introduction: The FDA FSMA standards stipulate composting conditions that meet acceptable treatments for use of manure/poultry litter-based biological soil amendments of animal origin (BSAAO). Application of FSMA-compliant BSAAO to soils for production of fresh produce is expected to result in reduced risk of pathogen contamination on the harvested produce when other stipulations in the Produce Safety rule are also implemented. However, meteorological conditions, geographic location, application methods, soil type, and bacterial populations can influence the presence of pathogenic bacteria, or their indicators (e.g., generic E. coli) and potential produce contamination.

Purpose: Evaluate survival of nonpathogenic E. coli (gEc) and Listeria spp.in tilled plots with both dairy and poultry litter composts in the northeastern United States.

Methods: Replicated field plots (2m2, n=24) of Loamy (L) or Sandy (S) soils were tilled and amended with dairy compost (DC), poultry litter compost (PLC), or no compost (NC). These plots were inoculated with a three-strain cocktail of rifampicin-resistant gEc at a rate of 8.7 log CFU/m2. Colony count and most probable number (MPN) methods were used to determine persistence of gEc in these plots over 104 days post-inoculation (dpi). Detection of indigenous Listeria spp. were also examined in all plots.

Results: At 104 dpi, inoculated gEc.survived at higher populations in PLC plots (3.5 to 3.80 log MPN/gdw) in comparison to DC plots (0.06 to 3.8 log MPN/gdw) and NC plots (0.6 to 1.3 log MPN/gdw). Populations of gEc and native E. coli after rainfall were independent of soil type. Listeriaspp. were found in PLC and DC, but not in NC plots.

Significance: Results are consistent with those from studies conducted in other regions of the United States that show that poultry litter-based BSAAO support greater numbers and longer periods of persistence in field soils of gEc than dairy-based BSAAO.

Back to: Poster Session 3 – Low-water Activity Foods, Packaging, Produce, Microbial Food Spoilage, Antimicrobials, Laboratory and Detection Methods, Water
<< Previous Abstract | Next Abstract >>