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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Environmental Microbial & Food Safety Laboratory » Research » Publications at this Location » Publication #365007

Research Project: Characterization and Mitigation of Bacterial Pathogens in the Fresh Produce Production and Processing Continuum

Location: Environmental Microbial & Food Safety Laboratory

Title: Presence of Salmonella and Listeria monocytogenes in reclaimed and surface irrigation water sources on Maryland's eastern shore: a Conserve study

item WHITE, CHANELLE - University Of Maryland Eastern Shore (UMES)
item HASHEM, FAWZY - University Of Maryland Eastern Shore (UMES)
item PARVEEN, SALINA - University Of Maryland Eastern Shore (UMES)
item MAY, ERIC - University Of Maryland Eastern Shore (UMES)
item HAYMAKER, JOSEPH - University Of Maryland Eastern Shore (UMES)
item Handy, Eric
item East, Cheryl - Roberts
item MICALLEF, SHIRLEY - University Of Maryland
item Sharma, Manan
item KNIEL, KALI - University Of Delaware
item SAPKOTA, AMY - University Of Maryland

Submitted to: International Association for Food Protection
Publication Type: Abstract Only
Publication Acceptance Date: 3/15/2019
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Introduction: Water scarcity is placing increasing pressure on traditional irrigation waters. This is leading to increased interest in the use of non-traditional water sources for the irrigation fresh produce. Therefore, ensuring the microbial safety of these water sources is paramount. Purpose: The purpose of this study was to determine the prevalence of Salmonella and Listeria monocytogenes in non-traditional irrigation water sources. Methods: Water samples (n=489) were collected over a two year period from two reclaimed water (RW) (n=105) and four surface water (SW) (n=384) sites on Maryland’s eastern shore from 2016 to 2018. Samples were collected by filtration using modified Moore swabs. Swabs were enriched in Universal Preerichment Broth followed by secondary enrichment in tetrathionate broth and Rappaport-Vassiliadis broth for Salmonella and Buffered Listeria Enrichment Broth for L. monocytogenes. Bacteria concentrations in the samples were quantified by real-time PCR using a modified MPN procedure using three volumes (10, 1, and 0.1 liters). Results: Of the 489 water samples collected, 346 (70.8%) of 489 and 160 (32.7%) of 489 were positive for Salmonella and L. monocytogenes, respectively. For both Salmonella and L. monocytogenes, MPN values varied among sites over the course of the study, ranging from zero to 11 MPN/l. For Salmonella, average MPN/l values for the SW sites were significantly higher (P<0.05) than the RW sites (2.47 and 0.84, respectively). For L. monocytogenes, average MPN/l values were 0.01 and 0.60 for RW and SW, respectively. Significance: This study shows that Salmonella and L. monocytogenes are present in nontraditional irrigation water sources on the eastern shore of Maryland. While these water sources have the potential to be utilized for fresh produce irrigation, development of mitigation strategies ensuring the safety of these water sources is also essential.