Correlation between E. coli levels and the presence of foodborne pathogens in surface irrigation water: Establishment of a sampling program

WATER RESEARCH

卷:128

Article

Truchado, Pilar¹  Hernandez, Natalia¹  Gil, Maria I.¹  Ivanek, Renata²  Allende, Ana¹ 

[1] CSIC, CEBAS, Res Grp Qual Safety & Bioact Plant Foods, Campus Univ Espinardo 25, Murcia 30100, Spain

[2] Cornell Univ, Coll Vet Med, Dept Populat Med & Diagnost Sci, Ithaca, NY 14853 USA

关键词: Indicator microorganisms;    Agricultural water;    Viable but non cultivable bacteria;    PMA-QPCR;    Sampling program;    Microbiological risk;    Fresh produce;   

DOI  :  10.1016/j.watres.2017.10.041

来源: Elsevier

【 摘 要 】

To establish the association between microbial indicators and the presence of foodborne pathogens in irrigation water, Escherichia coli was enumerated using two quantification methods (plate counts and PMA-qPCR) and presence/absence of pathogenic microorganisms, including five strains from the Shiga toxigenic E. coli (0157:H7, 026, 0103, 0111 and 0145) and Salmonella spp. were evaluated. The results confirmed that surface water can be considered a microbial hazard when used for irrigation. The levels of viable E. coli were very similar to those of cultivable E. coli, except for irrigation water obtained from water reservoirs. Comparison between the E. coli counts in samples positive and negative for the presence of pathogenic bacteria for the evaluated water sources identified E. coli level of 2.35 log cfu/100 mL as a cut-off able to correctly predict positive and negative samples with 93% sensitivity and 66% specificity, respectively. Thus, for the samples with levels of E. coli under 2.35 log cfu/100 mL (e.g., 2.24 log cfu/100 mL) there was a 90% probability that the samples were not contaminated with pathogenic microorganism in locations with similar prevalence. E. coli levels in irrigation water were affected by the ambient temperature confirming that water source and climate conditions should be taken into account by growers when designing a sampling program and the frequency of the monitoring to make a better and more efficient use of their resources. (C) 2017 Elsevier Ltd. All rights reserved.

【 授权许可】

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