Investigation of Microbial Safety and Correlations Between the Level of Sanitary Indicator Bacteria and the Detection Ratio of Pathogens in Agricultural Water

The microbial quality of agricultural water for fresh produce production is determined by the presence of fecal indicator bacteria (FIB) Escherichia coli despite poor correlations with pathogen presence. Additional FIB such as enterococci have been utilized for assessing water quality. The study objective was to determine the survival times (first time to detect zero or censored) of FIB ( E. coli , enterococci), surrogates ( Listeria innocua, L. seeligeri, Salmonella Typhimurium, PRD1), and pathogens (four strains each of pathogenic E. coli and L. monocytogenes ; five Salmonella serovars) simultaneously inoculated in freshwater mesocosms exposed to diel and seasonal variations. Six separate mesocosm experiments were conducted for ≤ 28 days each season with samples (sediment/water) collected each day for the first seven days and weekly thereafter. Microorganisms survived significantly longer in sediment compared to those in water [Hazard ratio (HR) for water/sediment is 2.2 (95%CI: 1.79, 2.71)]. Also, FIB E. coli survived significantly longer than FIB enterococci [HR for enterococci/ E.coli is 12.9 (95%CI: 8.18, 20.37)] after adjusting for the sediment/water and lake/river effects. Differences in the area under the curve (calculated from log CFU or PFU over time) were used to assess pathogen and surrogate survival in relation to FIB. Despite sample type (sediment/water) and seasonal influences, pathogenic Salmonella spp. survived similar to FIB E. coli , and L. monocytogenes and pathogenic E. coli survived similar to FIB enterococci. Further investigation of microbial survival in water and sediment is needed to determine which surrogates are best suited to assess pathogen survival in agricultural water used in in irrigation water for fresh produce. IMPORTANCE Contamination of fresh produce via agricultural water is well established. This research demonstrates that survival of fecal indicator bacteria, pathogenic microorganisms, and other bacterial and viral surrogates in freshwater differs by sample type (sediment/water) and season. Our work highlights potential risks associated with pathogen accumulation and survival in sediment, and the possibility for resuspension and contamination of agricultural water used in fresh produce production. Specifically, a greater microbial persistence in sediments versus water over time was observed, along with differences in survival among microorganisms in relation to fecal indicator bacteria E. coli and enterococci. Previous studies compared data among microbial groups in different environments. Conversely, fecal indicator bacteria, surrogates, and pathogenic microorganisms were assessed within the same water and sediment mesocosms in the present study during four seasons, better representing the agricultural aquatic environment. This data should be considered when determining agricultural microbial water quality criteria in fresh produce operations.

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Evaluation of Indicator Bacteria Export from an Urban Watershed

World Environmental and Water Resources Congress 2010 ◽

10.1061/41114(371)355 ◽

2010 ◽

Author(s):

J. M. Hathaway ◽

W. F. Hunt

Keyword(s):

Indicator Bacteria ◽

Urban Watershed

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1600 - Gastropods as a source for the faecal indicator bacteria enterococci and E. coli

10.26226/morressier.5b5199c3b1b87b000ecef036 ◽

2018 ◽

Author(s):

Michael Hügler ◽

Carolin Reitter

Keyword(s):

Indicator Bacteria ◽

Faecal Indicator Bacteria ◽

E Coli

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PHYSICOCHEMICAL AND MICROBIOLOGICAL EVALUATION OF HONEYS CONSUMED BY THE ELDERLY

Revista Prevenção de Infecção e Saúde ◽

10.26694/repis.v5i0.8815 ◽

2020 ◽

Vol 5 ◽

Author(s):

Lusmarina Rodrigues Silva ◽

Aline Marques Monte ◽

Rafael Gomes Abreu Bacelar ◽

Guilherme Antonio Silva Ribeiro ◽

Aline Maria Dourado Rodrigues ◽

...

Keyword(s):

Health Center ◽

Reducing Sugars ◽

The Elderly ◽

Indicator Bacteria ◽

Foreign Matter ◽

Total Sugars ◽

Significant Contamination ◽

Almost All ◽

Microbiological Analyses ◽

Current Standards

Objective: to analyze physicochemical, microbiological and dirt parameters in marketed honeys, consumed by the elderly cared for at Integrated Health Center in Teresina, Piauí, Brazil. Method: the following analyses were performed: color, water activity, humidity, ash, pH, acidity, reducing sugars, total sugars, apparent sucrose and insoluble solids. Contamination indicator bacteria, mesophilic microorganisms, filamentous fungi and yeasts, as well as dirt and foreign matter, performed in the period from April to June 2016. Results: analyses of ash, pH, acidity and insoluble solids were outside current standards. Microbiological analyses did not present significant contamination. Also, analyses of dirt showed insect fragments, foreign matter in almost all the samples. Conclusion: parameters of ash, pH, acidity and insoluble solids, as well as dirt and foreign matter, indicated that the samples were not in accordance with current legislation.

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