P3-86 Endemic Salmonella Contamination of the Virginian Eastern Shore Tomato Production Environment

Wednesday, July 25, 2012
Exhibit Hall (Rhode Island Convention Center)
Rebecca Bell, U.S. Food and Drug Administration, College Park , MD
Jie Zheng, U.S. Food and Drug Administration, College Park, MD
Sarah Allard, U.S. Food and Drug Administration, College Park , MD
Erik Burrows, U.S. Food and Drug Administration, College Park, MD
Charles Wang, U.S. Food and Drug Administration, College Park, MD
Gabriela Arce, U.S. Food and Drug Administration, College Park , MD
Tim Muruvanda, U.S. Food and Drug Administration, College Park, MD
Christine Keys, U.S. Food and Drug Administration, College Park, MD
David Melka, U.S. Food and Drug Administration, College Park, MD
Marc Allard, U.S. Food and Drug Administration, College Park, MD
Steven Rideout, Virginia Tech, Painter, VA
Eric Brown, U.S. Food and Drug Administration, College Park, MD
 

Introduction: Non-typhoidal Salmonella species are responsible for an estimated 1 million foodborne illnesses every year in the U. S. Tomatoes grown along the Eastern Shore of Virginia are implicated almost yearly in Salmonella outbreaks. 

Purpose: The results of a four-month survey conducted in the summer of 2011 for environmental Salmonella on Virginia’s Eastern Shore (VES) are presented.

Methods: Samples were collected at Virginia Tech Agricultural Research Extension Center from June to September. To ascertain the prevalence of Salmonella in VES waterways, six additional creeks were sampled. For each collection, 84 to 255 samples of soil, sediment, water, insects, produce and vegetation were enriched in modified buffered peptone water and tested for Salmonella using a multiplex, real-time PCR (qPCR) assay. The qPCR tested for the Salmonella specific markers, invA and apeE along with gapA, a marker for Enterobacteriaceae, and an internal amplification control. Subsets of samples were also cultured for isolation of Salmonella.

Results: The incidence of Salmonella detection via the real-time PCR method was the highest in September. These samples were collected after Hurricane Irene and do not follow the trend of detection seen in previous years. Data from June to August do follow the previous trend showing the highest incidence in June and decreasing each subsequent month. Over 200 isolates, 17+ serovars including Newport and Javiana, were recovered. The majority of these isolates came from the various waterways along the VES. Also the most serotype diversity was observed in the isolates from VES waterways.

Significance: This suggests that Salmonella has established itself as an environmental resident along the VES. Several isolates were obtained from goose feces suggesting a possible mechanism of spread of Salmonella throughout this environment. Many of these isolates are undergoing whole genome sequencing to gain a greater understanding of this resident environmental population.