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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 #337533

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

Location: Environmental Microbial & Food Safety Laboratory

Title: Prevalence of E. coli, Salmonella spp. and L. monocytogenes in non-traditional irrigation waters in the Mid-Atlantic U.S.: a conserve project

item Handy, Eric
item East, Cheryl - Roberts
item CALLAHAN, MARY - University Of Maryland
item ALLARD, SARAH - University Of Maryland
item CRADDOCK, HILLARY - University Of Maryland
item HAYMAKER, JOSEPH - University Of Maryland Eastern Shore (UMES)
item MICALLEF, SHIRLEY - University Of Maryland
item KNIEL, KALMIA - University Of Delaware
item HASHEM, FAWZY - University Of Maryland Eastern Shore (UMES)
item PARVEEN, SALINA - University Of Maryland Eastern Shore (UMES)
item MARY, ERIC - University Of Maryland Eastern Shore (UMES)
item SAPKOTA, AMY - University Of Maryland
item Sharma, Manan

Submitted to: International Association for Food Protection
Publication Type: Abstract Only
Publication Acceptance Date: 3/17/2017
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Introduction: Surface and non-traditional irrigation water (SNIW) sources can increase the irrigation water supplies without consuming potable water. However, these sources must be evaluated for enteric pathogens that could adulterate crops intended for human consumption and comply with Food Safety Modernization Act (FSMA) irrigation water standards. Purpose: To evaluate surface (non-tidal freshwater (NF), tidal freshwater (TF), pond water (PW), tidal brackish (TB)) water sources from 8 sites in Maryland for the presence of Salmonella spp., Listeria monocytogenes(Lm), and E. coli(Ec). Methods: SNIW from 8 sites (4 NF, 1 TB, 1 TF, and 2 PW) were collected by traditional methods or filtered through modified Moore swabs. Sampling occurred on 6 different dates (Sept–Dec 2016). Filters were quantified for E. coli populations (n=52) through standard methods (EPA 1604) and Moore swabs were quantified for Salmonella spp. (n=32) and Lm populations (n=36) through a modified MPN procedure using 10L, 1L and 0.1L volumes. Chemical parameters of water were measured. Culture-positive results for Salmonella and Lm were confirmed through real-time PCR. One-way ANOVA on recovered pathogen populations in JMP were performed. Results: Mean Salmonella populations were 0.15+0.30, 0.11+0.10, 0.02+0.14, and 0.007+0.012 MPN/100mL from NF, TF, TB and PW sources, respectively. Mean Lm populations were 0.20+0.08, 0.28+0.17, 0.004+0.15, and 0.003+0.10 MPN/100mL, respectively. Mean Salmonella populations were significantly (p<0.05) higher at one NF site (MD05) compared to other sites. Lm populations at one NF site (MD08) were also significantly higher compared to other sites. From all water samples, 65% and 46% were positive for Salmonella spp. and Lm, respectively, and 53% contained Ec populations > 126 CFU/100mL. There were no significant correlations observed between Ec and either Lm or Salmonella populations. Significance: These data indicate that Salmonella and Lm are present in multiple SNIW sources in Maryland, and year-round sampling is required to truly assess prevalence in this region.