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Agricultural and management practices and bacterial contamination in greenhouse versus open field lettuce production.

Holvoet K, Sampers I, Seynnaeve M, Jacxsens L, Uyttendaele M - Int J Environ Res Public Health (2014)

Bottom Line: The aim of this study was to gain insight into potential differences in risk factors for microbial contamination in greenhouse versus open field lettuce production.These data were combined with results of analysis on the levels of Escherichia coli as a fecal indicator organism and the presence of enteric bacterial pathogens on both lettuce crops and environmental samples.These results indicate the need for further elaboration of specific guidelines and control measures for leafy greens with regard to microbial hazards.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Food Microbiology and Food Preservation, Department of Food Safety and Food Quality, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, Ghent B-9000, Belgium. kevin.holvoet@ugent.be.

ABSTRACT
The aim of this study was to gain insight into potential differences in risk factors for microbial contamination in greenhouse versus open field lettuce production. Information was collected on sources, testing, and monitoring and if applicable, treatment of irrigation and harvest rinsing water. These data were combined with results of analysis on the levels of Escherichia coli as a fecal indicator organism and the presence of enteric bacterial pathogens on both lettuce crops and environmental samples. Enterohemorragic Escherichia coli (EHEC) PCR signals (vt1 or vt2 positive and eae positive), Campylobacter spp., and Salmonella spp. isolates were more often obtained from irrigation water sampled from open field farms (21/45, 46.7%) versus from greenhouse production (9/75, 12.0%). The open field production was shown to be more prone to fecal contamination as the number of lettuce samples and irrigation water with elevated E. coli was significantly higher. Farmers comply with generic guidelines on good agricultural practices available at the national level, but monitoring of microbial quality, and if applicable appropriateness of water treatment, or water used for irrigation or at harvest is restricted. These results indicate the need for further elaboration of specific guidelines and control measures for leafy greens with regard to microbial hazards.

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Degree of contamination of the different indicator bacteria (log CFU/100 ml) (A) and pathogens (presence/absence in 1 l) (B) for borehole water (farms 3 and 4) and open well water (farms 1, 2, 5–8). (C) Impact of water treatment on the indicator bacteria and pathogens by comparing treated and untreated water for three farms applying water treatment (farms 1, 3 and 4). Bars show the 95% confident interval.
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ijerph-12-00032-f004: Degree of contamination of the different indicator bacteria (log CFU/100 ml) (A) and pathogens (presence/absence in 1 l) (B) for borehole water (farms 3 and 4) and open well water (farms 1, 2, 5–8). (C) Impact of water treatment on the indicator bacteria and pathogens by comparing treated and untreated water for three farms applying water treatment (farms 1, 3 and 4). Bars show the 95% confident interval.

Mentions: Of the eight farms, two farms used borehole water as the water source for irrigation compared to open well water for the other six farms. There was a significantly higher number of samples with elevated levels of E. coli, coliforms, enterococci, and TPAC in the open well water compared to the borehole water (P < 0.05, MW and t-test for TPAC) (Figure 4A). The prevalence of pathogens was also lower in the borehole water compared to the open well water (Figure 4B).


Agricultural and management practices and bacterial contamination in greenhouse versus open field lettuce production.

Holvoet K, Sampers I, Seynnaeve M, Jacxsens L, Uyttendaele M - Int J Environ Res Public Health (2014)

Degree of contamination of the different indicator bacteria (log CFU/100 ml) (A) and pathogens (presence/absence in 1 l) (B) for borehole water (farms 3 and 4) and open well water (farms 1, 2, 5–8). (C) Impact of water treatment on the indicator bacteria and pathogens by comparing treated and untreated water for three farms applying water treatment (farms 1, 3 and 4). Bars show the 95% confident interval.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4306849&req=5

ijerph-12-00032-f004: Degree of contamination of the different indicator bacteria (log CFU/100 ml) (A) and pathogens (presence/absence in 1 l) (B) for borehole water (farms 3 and 4) and open well water (farms 1, 2, 5–8). (C) Impact of water treatment on the indicator bacteria and pathogens by comparing treated and untreated water for three farms applying water treatment (farms 1, 3 and 4). Bars show the 95% confident interval.
Mentions: Of the eight farms, two farms used borehole water as the water source for irrigation compared to open well water for the other six farms. There was a significantly higher number of samples with elevated levels of E. coli, coliforms, enterococci, and TPAC in the open well water compared to the borehole water (P < 0.05, MW and t-test for TPAC) (Figure 4A). The prevalence of pathogens was also lower in the borehole water compared to the open well water (Figure 4B).

Bottom Line: The aim of this study was to gain insight into potential differences in risk factors for microbial contamination in greenhouse versus open field lettuce production.These data were combined with results of analysis on the levels of Escherichia coli as a fecal indicator organism and the presence of enteric bacterial pathogens on both lettuce crops and environmental samples.These results indicate the need for further elaboration of specific guidelines and control measures for leafy greens with regard to microbial hazards.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Food Microbiology and Food Preservation, Department of Food Safety and Food Quality, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, Ghent B-9000, Belgium. kevin.holvoet@ugent.be.

ABSTRACT
The aim of this study was to gain insight into potential differences in risk factors for microbial contamination in greenhouse versus open field lettuce production. Information was collected on sources, testing, and monitoring and if applicable, treatment of irrigation and harvest rinsing water. These data were combined with results of analysis on the levels of Escherichia coli as a fecal indicator organism and the presence of enteric bacterial pathogens on both lettuce crops and environmental samples. Enterohemorragic Escherichia coli (EHEC) PCR signals (vt1 or vt2 positive and eae positive), Campylobacter spp., and Salmonella spp. isolates were more often obtained from irrigation water sampled from open field farms (21/45, 46.7%) versus from greenhouse production (9/75, 12.0%). The open field production was shown to be more prone to fecal contamination as the number of lettuce samples and irrigation water with elevated E. coli was significantly higher. Farmers comply with generic guidelines on good agricultural practices available at the national level, but monitoring of microbial quality, and if applicable appropriateness of water treatment, or water used for irrigation or at harvest is restricted. These results indicate the need for further elaboration of specific guidelines and control measures for leafy greens with regard to microbial hazards.

Show MeSH
Related in: MedlinePlus