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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 #336895
Research Project: Characterization and Mitigation of Bacterial Pathogens in the Fresh Produce Production and Processing Continuum

Location: Environmental Microbial & Food Safety Laboratory

Title: Assessment of microbial quality of reclaimed water, roof-harvest water, and creek water for irrigation

Author
item YIN, HSIN-BAI - University Of Maryland
item Green, Jennifer
item Patel, Jitu

Submitted to: International Food Technology Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 3/18/2017
Publication Date: 6/25/2017
Citation: Yin, H., Green, J.A., Patel, J.R. 2017. Assessment of microbial quality of reclaimed water, roof-harvest water, and creek water for irrigation. International Food Technology Meeting Abstracts. p.06-53. June 24-28, 2017.

Interpretive Summary:

Technical Abstract: The availability of water for crop irrigation is decreasing due to droughts, population growth, and pollution. Food Safety and Modernization Act (FSMA) for irrigation water standards may also discourage growers to use poor microbial quality water for produce crop irrigation. Reclaimed water use for irrigation is restricted on fresh produce. Individual households also collect rainwater for watering vegetable garden. We evaluated microbial quality of alternative water including reclaimed water (RCW), roof-harvest water (RHW), and creek water (CW) to ascertain if it meets FSMA microbial quality criteria. In this study, the microbial quality of alternative water was assessed by monitoring the populations of Escherichia coli, enterococci, total coliforms, fecal coliforms, Bacteroides spp., Clostridium perfringens, and pathogens (Salmonella, Listeria, and E. coli O157:H7). Water samples were analyzed by two detection methods including membrane filter technique and an innovative concentrator analysis. Briefly, 100 ml of each water sample was filtered with 0.45 µm-pore-size filter or concentrated to ~250 µl using the concentrator and were directly enumerated on specific agars. Bacterial counts were recorded after incubation and expressed in log CFU/100 ml in both methods. In total, 14 samples of alternative water were analyzed including 4 RCW, 5 RHW, and 5 CW. Results revealed no significant difference between two detection methods when enumerating total coliforms, E. coli, and enterococci. Fecal coliforms of RCW, RHW, and CW analyzed by the membrane filter and concentrator were 4.3 and 2.8, 1.6 and 0.7, and 1.7 and 1.1 log CFU/100ml, respectively. In addition, E. coli populations from RHW and CW samples were below the FSMA criteria (2.1 log CFU/100ml). Of the 14 samples, 2 RCW were Bacteroides positive and 4 RCW, 3 RHW, and 3 CW were C. perfringens positive. Moreover, membrane filter method detected 1 RCW presumptive Salmonella positive and 3 RHW and 2 CW presumptive Listeria positive. Results suggest that RHW and CW can be used for irrigation purpose based on their microbial quality; however, remediation of RCW is required prior to use for irrigation of fresh produce.