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cThe impact of proximity to a beef cattle feedlot on Escherichia coli O157:H7 contamination of leafy greens was examined. In each of 2 years, leafy greens were planted in nine plots located 60, 120, and 180 m from a cattle feedlot (3 plots at each distance). Leafy greens (270) and feedlot manure samples (100) were collected six different times from June to September in each year. Both E. coli O157:H7 and total E. coli bacteria were recovered from leafy greens at all plot distances. E. coli O157:H7 was recovered from 3.5% of leafy green samples per plot at 60 m, which was higher (P < 0.05) than the 1.8% of positive samples per plot at 180 m, indicating a decrease in contamination as distance from the feedlot was increased. Although E. coli O157:H7 was not recovered from air samples at any distance, total E. coli was recovered from air samples at the feedlot edge and all plot distances, indicating that airborne transport of the pathogen can occur. Results suggest that risk for airborne transport of E. coli O157:H7 from cattle production is increased when cattle pen surfaces are very dry and when this situation is combined with cattle management or cattle behaviors that generate airborne dust. Current leafy green field distance guidelines of 120 m (400 feet) may not be adequate to limit the transmission of E. coli O157:H7 to produce crops planted near concentrated animal feeding operations. Additional research is needed to determine safe set-back distances between cattle feedlots and crop production that will reduce fresh produce contamination.T he consumption of fresh produce increasingly has been linked to human food-borne disease (1-4). In particular, leafy vegetables, such as spinach and lettuce, have become significant vehicles for the transmission of food-borne pathogens. Produce-associated outbreak surveillance data from the Centers for Disease Control and Prevention (CDC) for the period from 2000 to 2009 showed that among produce commodities, leafy greens were the most frequently linked to outbreaks (5). An analysis of published reports of U.S. fresh produce-associated outbreaks with an attribution risk ranking tool categorized the combination of leafy greens and Escherichia coli O157:H7 with the highest risk ranking score, followed by Salmonella enterica in tomatoes ranking second and S. enterica in leafy greens ranking third (6). For all U.S. foodborne disease outbreaks caused by Shiga toxin-producing E. coli (STEC) in the period of 1998 to 2008, leafy vegetables were the second most common implicated commodity, following beef (2). In addition, spinach, lettuce, and cilantro were commodities most associated with the recovery of STEC in produce market basket surveys conducted within the USDA Agricultural Marketing Service Microbiological Data Program from 2002 to 2012 (7). Leafy greens typically are consumed raw, so protecting these products from microbial contamination in the preharvest environment is critical to reducing the risk for food-borne illness. Potential sources of pathogens for preharvest produ...

The incidence and severity of disease associated with toxigenic Clostridium difficile have increased in hospitals in North America from the emergence of newer, more virulent strains. Toxigenic C. difficile has been isolated from food animals and retail meat with potential implications of transfer to human beings. The objective of the present study was to determine the prevalence of toxigenic C. difficile in chickens and retail poultry meat in Texas. Seven C. difficile isolates were detected in fecal samples of 300 (2.3%) broiler chickens. Three cultivation procedures were evaluated for isolation of C. difficile from poultry meat and detected 1/32 (3.1%), 2/32 (6.2%), and 4/32 (12.5%) for the three procedures, respectively. Chicken and poultry meat isolates were characterized as toxinotype V and pulsed-field gel electrophoresis gel type-NAP7 or NAP7-variant. Susceptibilities to 11 antimicrobial agents in the current study suggested somewhat reduced resistance than reported for other meat or animal toxinotype V isolates.