title: Prevalence and Phylogenetic Characterization of Escherichia coli and Hygiene Indicator Bacteria Isolated from Leafy Green Produce, Beef, and Pork Obtained from Farmers' Markets in Pennsylvania.
abstract: The popularity of farmers' markets in the United States has led to over 8,400 farmers' markets being in operation in 2015. As farmers' markets have increased in size and complexity in the kinds of foods sold at these venues, so have the potential food safety risks. Since 2008, seven major foodborne illness outbreaks and two recalls associated with food products from farmers' markets have occurred, causing 80 known reported illnesses and one death. Various researchers also have observed vendors performing high-risk food safety retail behaviors, and others have identified microbiological hazards in foods sold at farmers' markets. In this study, the presence of hygiene indicators (coliforms, fecal coliforms, Listeria spp., and Escherichia coli ) was assessed in select samples of leafy green produce and meat obtained from farmers' markets in Pennsylvania. E. coli isolates were further characterized by phylogenetic profile and virulence potential. E. coli was present in 40% (20 of 50) and 18% (9 of 50) of beef and pork samples, respectively, and in 28% (15 of 54), 29% (15 of 52), and 17% (8 of 46) of kale, lettuce, and spinach samples, respectively. Listeria spp. was found in 8% (4 of 50) of beef samples, 2% (1 of 54) of kale samples, 4% (2 of 52) of lettuce samples, and 7% (3 of 46) of spinach samples. Among the 10 Listeria spp. isolates, 3 were identified as L. monocytogenes . E. coli isolated from meat samples mainly clustered into phylogroup B1 (66%; 19 of 29), whereas produce isolates clustered into phylogroups B2 (36%; 14 of 39) and B1 (33%; 13 of 39). These E. coli isolates possessed the fimH, iroN, hlyD, and eae genes associated with extraintestinal pathogenic E. coli and Shiga toxin-producing E. coli . The high prevalence but low levels of E. coli and Listeria spp. found on both produce and meat products obtained from farmers' markets in this study strongly indicate that farmers' market vendors would benefit greatly from food safety training and increased public health oversight.
authors.affiliation: Department of Food Science, 202 Food Science Building, 115 Henning Building, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: Joshua A
authors.initials: JA
authors.lastname: Scheinberg
authors.affiliation: Department of Food Science, 202 Food Science Building, 115 Henning Building, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: Edward G
authors.initials: EG
authors.lastname: Dudley
authors.affiliation: Department of Animal Sciences, 350 Agricultural Science and Industries Building, 115 Henning Building, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Campbell
authors.affiliation: Department of Veterinary and Biomedical Sciences, 115 Henning Building, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: Beth
authors.initials: B
authors.lastname: Roberts
authors.affiliation: Department of Food Science, 202 Food Science Building, 115 Henning Building, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: DiMarzio
authors.affiliation: Department of Veterinary and Biomedical Sciences, 115 Henning Building, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: Chitrita
authors.initials: C
authors.lastname: DebRoy
authors.affiliation: Department of Food Science, 202 Food Science Building, 115 Henning Building, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: Catherine N
authors.initials: CN
authors.lastname: Cutter
mesh_terms: D000818:Animals; D001419:Bacteria; D004926:Escherichia coli / Q000302:isolation & purification*; D000067565:Farmers; D005516:Food Microbiology; D006920:Hygiene; D010414:Pennsylvania; D010802:Phylogeny; D015995:Prevalence; D000069466:Red Meat; D013552:Swine; D014675:Vegetables / Q000382:microbiology
keywords: Escherichia coli; Farmers' markets; Hygiene indicators; Leafy green produce; Phylogeny