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ARS Home » Southeast Area » Athens, Georgia » U.S. National Poultry Research Center » Egg and Poultry Production Safety Research Unit » Research » Publications at this Location » Publication #391263

Research Project: Reduction of Foodborne Pathogens and Antimicrobial Resistance in Poultry Production Environments

Location: Egg and Poultry Production Safety Research Unit

Title: Bacterial sampling from organic farms demonstrates importance of cleaning produce before consumption

Author
item WIERSMA, CRYSTAL - Colorado State University
item OLADEINDE, ADELUMOLA - US Department Of Agriculture (USDA)
item ABDO, ZAID - Colorado State University
item ZIMERI, ANNE MARIE - University Of Georgia
item Cudnik, Denice
item Plumblee Lawrence, Jodie
item CONSORTIUM, HARVEST - University Of Georgia

Submitted to: ASM Conference
Publication Type: Abstract Only
Publication Acceptance Date: 2/24/2022
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: A two-year longitudinal study was conducted to address the microbiological quality of environmental and Zucchini squash samples from organic farms using biological soil amendments of animal origin (BSAAO). Samples were collected from four farms in the field and at the farmer’s market point-of-sale. Three farms used non-composted broiler litter and a fourth control farm used coffee grounds. Salmonella (n = 1 positive) and Campylobacter (n = 4 positives) were sporadically detected in the BSAAO and soil, while Listeria and Shiga toxin-producing E. coli were not detected. Squash from the control farm carried lower levels of indicator bacteria (coliforms and enterococci) than farms that used broiler litter. In addition, indicator bacteria were higher on the outside than on the inside of squash. Washing prior to sale at the farmer’s market reduced the exterior bacterial load in squash. Antibiotic susceptibility testing and whole genome sequencing revealed that Enterobacter spp., Serratia spp., and Pantoea spp. were the dominant coliforms harboring antimicrobial resistance (AMR), while Enterococcus faecalis and a group of novel vancomycin resistant Enterococcus spp. were the Enterococcus spp. carrying AMR. We found that ~95% of the AMR genes (n =145) were encoded in regions of the chromosome that lacked genomic signatures for horizontal gene transfer and suggests that the risk of AMR transfer to other bacterial species is low. These results show that organic produce can be a reservoir of AMR and emphasize the importance of cleaning produce before consumption.