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Risk Factors for Salmonella, Shiga Toxin-Producing Escherichia coli and Campylobacter Occurrence in Primary Production of Leafy Greens and Strawberries.

Ceuppens S, Johannessen GS, Allende A, Tondo EC, El-Tahan F, Sampers I, Jacxsens L, Uyttendaele M - Int J Environ Res Public Health (2015)

Bottom Line: A significant association between elevated numbers of generic E. coli and detection of pathogens (OR of 2.3 for STEC and 2.7 for Salmonella) was established.Generic E. coli was found to be a suitable index organism for Salmonella and STEC, but to a lesser extent for Campylobacter.Guidelines on frequency of sampling and threshold values for E. coli in irrigation water may differ from region to region.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Food Microbiology and Food Preservation (LFMFP), Department of Food Safety and Food Quality, Faculty of Bioscience Engineering, Ghent University, Ghent 9000, Belgium. Siele.Ceuppens@UGent.be.

ABSTRACT
The microbiological sanitary quality and safety of leafy greens and strawberries were assessed in the primary production in Belgium, Brazil, Egypt, Norway and Spain by enumeration of Escherichia coli and detection of Salmonella, Shiga toxin-producing E. coli (STEC) and Campylobacter. Water samples were more prone to containing pathogens (54 positives out of 950 analyses) than soil (16/1186) and produce on the field (18/977 for leafy greens and 5/402 for strawberries). The prevalence of pathogens also varied markedly according to the sampling region. Flooding of fields increased the risk considerably, with odds ratio (OR) 10.9 for Salmonella and 7.0 for STEC. A significant association between elevated numbers of generic E. coli and detection of pathogens (OR of 2.3 for STEC and 2.7 for Salmonella) was established. Generic E. coli was found to be a suitable index organism for Salmonella and STEC, but to a lesser extent for Campylobacter. Guidelines on frequency of sampling and threshold values for E. coli in irrigation water may differ from region to region.

No MeSH data available.


Related in: MedlinePlus

(a) Effect of the irrigation water type; (b) flooding events; (c) generic E. coli concentrations on the estimated risk of Salmonella presence by multiple logistic regression (Table 3).
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ijerph-12-09809-f002: (a) Effect of the irrigation water type; (b) flooding events; (c) generic E. coli concentrations on the estimated risk of Salmonella presence by multiple logistic regression (Table 3).

Mentions: Figure 2, Figure 3 and Figure 4 graphically illustrate the results from the logistic models presented in Table 5. The prevalence of Salmonella and STEC was estimated to increase in case of higher generic E. coli counts (Figure 2a and Figure 3). The odds ratio (OR) ranged from 2.3 to 2.7, meaning that an increase of 1.0 log CFU per g or per 100 mL of generic E. coli doubles to triples the odds of finding pathogens. There were no interactions of E. coli counts with other factors, meaning that this effect applied to all countries involved in the present study and all sample types included (i.e., produce, soil and water). Salmonella and Campylobacter prevalence differed significantly between countries and thus the risk estimates are specifically adjusted for each country. Detection of Salmonella was more likely if surface water was used for irrigation, followed by ground water, next collected rainfall water and it was least likely if municipal potable water was used (Figure 2b). Our study confirmed once more that surface water is most frequently contaminated with pathogens relative to other irrigation water sources such as rain and ground water [33,67,68]. When sampling within one week of a flooding event, the odds for Salmonella presence increased 10.9-fold (Figure 2c) and that for STEC 7.7-fold (Figure 3). Storage of irrigation water in open reservoirs prior to use was significantly associated with increased likelihood of Campylobacter detection (OR = 3.5). In particular water samples contained significantly more often Campylobacter than fresh produce samples (OR ≥ 12.5) and samples (of any type) taken in greenhouses showed significantly less Campylobacter than samples taken in open field farms (OR = 0.2), but there was an interaction between sample type and the farm type (open fields vs. greenhouses). This means that the ORs of sample type and farm type are not constant but vary depending on the value of the other factor. Specifically for this model, it means that the probability of finding Campylobacter was higher for irrigation water in open field farms than irrigation water in greenhouses, but Campylobacter prevalence was lower in leafy greens from open fields than leafy greens grown in greenhouses (Figure 4). Irrigation water in greenhouses presented a lower risk for Campylobacter, which could be explained by the more often use of reclaimed water (reuse of water after disinfection treatment) and/or the use of municipal potable water. However, the fresh produce itself grown in greenhouses seems to be more likely to finding Campylobacter than upon cultivation in open fields. This might be due to the exclusion of birds, lower exposure to solar UV radiation and the usually higher relative humidity in greenhouses enabling prolonged survival of microorganisms in general, and of Campylobacter in particular [69,70].


Risk Factors for Salmonella, Shiga Toxin-Producing Escherichia coli and Campylobacter Occurrence in Primary Production of Leafy Greens and Strawberries.

Ceuppens S, Johannessen GS, Allende A, Tondo EC, El-Tahan F, Sampers I, Jacxsens L, Uyttendaele M - Int J Environ Res Public Health (2015)

(a) Effect of the irrigation water type; (b) flooding events; (c) generic E. coli concentrations on the estimated risk of Salmonella presence by multiple logistic regression (Table 3).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4555313&req=5

ijerph-12-09809-f002: (a) Effect of the irrigation water type; (b) flooding events; (c) generic E. coli concentrations on the estimated risk of Salmonella presence by multiple logistic regression (Table 3).
Mentions: Figure 2, Figure 3 and Figure 4 graphically illustrate the results from the logistic models presented in Table 5. The prevalence of Salmonella and STEC was estimated to increase in case of higher generic E. coli counts (Figure 2a and Figure 3). The odds ratio (OR) ranged from 2.3 to 2.7, meaning that an increase of 1.0 log CFU per g or per 100 mL of generic E. coli doubles to triples the odds of finding pathogens. There were no interactions of E. coli counts with other factors, meaning that this effect applied to all countries involved in the present study and all sample types included (i.e., produce, soil and water). Salmonella and Campylobacter prevalence differed significantly between countries and thus the risk estimates are specifically adjusted for each country. Detection of Salmonella was more likely if surface water was used for irrigation, followed by ground water, next collected rainfall water and it was least likely if municipal potable water was used (Figure 2b). Our study confirmed once more that surface water is most frequently contaminated with pathogens relative to other irrigation water sources such as rain and ground water [33,67,68]. When sampling within one week of a flooding event, the odds for Salmonella presence increased 10.9-fold (Figure 2c) and that for STEC 7.7-fold (Figure 3). Storage of irrigation water in open reservoirs prior to use was significantly associated with increased likelihood of Campylobacter detection (OR = 3.5). In particular water samples contained significantly more often Campylobacter than fresh produce samples (OR ≥ 12.5) and samples (of any type) taken in greenhouses showed significantly less Campylobacter than samples taken in open field farms (OR = 0.2), but there was an interaction between sample type and the farm type (open fields vs. greenhouses). This means that the ORs of sample type and farm type are not constant but vary depending on the value of the other factor. Specifically for this model, it means that the probability of finding Campylobacter was higher for irrigation water in open field farms than irrigation water in greenhouses, but Campylobacter prevalence was lower in leafy greens from open fields than leafy greens grown in greenhouses (Figure 4). Irrigation water in greenhouses presented a lower risk for Campylobacter, which could be explained by the more often use of reclaimed water (reuse of water after disinfection treatment) and/or the use of municipal potable water. However, the fresh produce itself grown in greenhouses seems to be more likely to finding Campylobacter than upon cultivation in open fields. This might be due to the exclusion of birds, lower exposure to solar UV radiation and the usually higher relative humidity in greenhouses enabling prolonged survival of microorganisms in general, and of Campylobacter in particular [69,70].

Bottom Line: A significant association between elevated numbers of generic E. coli and detection of pathogens (OR of 2.3 for STEC and 2.7 for Salmonella) was established.Generic E. coli was found to be a suitable index organism for Salmonella and STEC, but to a lesser extent for Campylobacter.Guidelines on frequency of sampling and threshold values for E. coli in irrigation water may differ from region to region.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Food Microbiology and Food Preservation (LFMFP), Department of Food Safety and Food Quality, Faculty of Bioscience Engineering, Ghent University, Ghent 9000, Belgium. Siele.Ceuppens@UGent.be.

ABSTRACT
The microbiological sanitary quality and safety of leafy greens and strawberries were assessed in the primary production in Belgium, Brazil, Egypt, Norway and Spain by enumeration of Escherichia coli and detection of Salmonella, Shiga toxin-producing E. coli (STEC) and Campylobacter. Water samples were more prone to containing pathogens (54 positives out of 950 analyses) than soil (16/1186) and produce on the field (18/977 for leafy greens and 5/402 for strawberries). The prevalence of pathogens also varied markedly according to the sampling region. Flooding of fields increased the risk considerably, with odds ratio (OR) 10.9 for Salmonella and 7.0 for STEC. A significant association between elevated numbers of generic E. coli and detection of pathogens (OR of 2.3 for STEC and 2.7 for Salmonella) was established. Generic E. coli was found to be a suitable index organism for Salmonella and STEC, but to a lesser extent for Campylobacter. Guidelines on frequency of sampling and threshold values for E. coli in irrigation water may differ from region to region.

No MeSH data available.


Related in: MedlinePlus