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P3-53 Evaluation of Modified Semisolid Rappaport Vassiliadis Motility Agar (MSRV) as a Selective Enrichment Medium for the Isolation of Salmonella from Mung Bean, Alfalfa, and Clover Sprouts with the Bacteriological Analytical Manual (BAM)

Tuesday, July 28, 2015
Hall B (Oregon Convention Center)
Andrew Jacobson , U.S. Food and Drug Adminstration , College Park , MD
Hua Wang , U.S. Food and Drug Administration , College Park , MD
Vikas Gill , U.S. Food and Drug Administration , College Park , MD
Stuart Chirtel , U.S. Food and Drug Administraion , College Park , MD
Aparna Tatavarthy , U.S. Food and Drug Administration , College Park , MD
Thomas Hammack , U.S. Food and Drug Administration , College Park , MD
Introduction: A variety of sprout types have been identified as sources of Salmonella.  Development of a culture method for use with sprouts will benefit sprout surveillance efforts and assist in identifying origins of contamination in sprout related outbreaks.    

Purpose: Modified Semisolid Rappaport Vassiliadis (MSRV) motility agar is evaluated as a selective enrichment medium in isolating Salmonella from artificially contaminated test portions of alfalfa, mung bean, and clover sprouts. 

Methods: Comparison of Fractional Positive Values (FPV) for MSRV, RV, and TT selective enrichment media were performed with Fisher’s Exact 2-tailed F-test (P < 0.05).  The FPV is that number of test portions identified as positive among 20 analyzed.  Preenrichments were performed with Lactose broth (LB; BAM method) and Universal Preenrichment Broth (UPB).  FPVs of the preenrichment media/selective enrichment media were also compared to evaluate effectiveness of LB and UPB (P < 0.05)

Results: RV media was more effective than TT and MSRV (FPVs of 6, 1, and 0) in isolating Salmonella Newport from mung beans, as was UPB over LB (all FPVs = 0) (P < 0.05).  For isolating Salmonella Stanley and Salmonella Oranienburg from clover sprouts with LB preenrichment media, respective FPVs for TT of 8 and 13 were higher than FPVs for RV and MSRV of 0 (P < 0.05).  The FPVs for MSRV were lower than FPVs for RV and TT with UPB preenrichment media (P < 0.05).  No differences in FPVs occurred in trials with alfalfa sprouts except between UPB and LB with UPB being more effective as preenrichment media (P < 0.05).    

Significance: The use of MSRV for the isolation of Salmonella from alfalfa, mung bean, and clover sprouts is not recommended, however UPB is more effective as preenrichment media than LB for these sprout types (P < 0.05).

Back to: Poster Session 3 – Laboratory and Detection Methods, Sanitation; Antimicrobials; Produce; Epidemiology
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