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Potential cross-contamination of E. coli between lettuce and wash water simulating an industrial fresh-cut lettuce wash process

Kevin Holvoet (UGent) , Imca Sampers (UGent) , Sam Van Haute (UGent) , Liesbeth Jacxsens (UGent) and Mieke Uyttendaele (UGent)
Author
Organization
Project
  • VEG-I-TRADE (Impact of climate change and globalisation on safety of fresh produce – governing a supply chain of uncompromised food sovereignty)
Abstract
The aim was to provide information about E. coli contamination of washing water to prevent water becoming a vehicle for transfer of microbial contamination to lettuce and to get insight on the factors affecting proper water management. A lettuce wash process was simulated to determine (1) the ability to use “clean” water and the tolerable E. coli levels for “clean” water and its’ potential to respect it upon re-use of water in the first washing bath, (2) the need and effect of using potable water in the second washing bath, (3) the use of a final rinsing step after washing to reduce the microbial contamination level of lettuce, (4) the influence of initial E. coli contamination levels of lettuce on the washing bath water quality and (5) the use of chlorine to control the water quality in the first washing bath (prevent cross-contamination of lettuce). Due to transfer via drain water of washed lettuce, the contamination level of the “clean (re-used) water” in the first wash bath determined the contamination of the second wash bath (aimed to be potable water). For lower contaminations (<4 log E. coli/100 ml), the washing water did not transfer unacceptable levels of E. coli to the washed lettuce and no influence of the product/water ratio (kg/l) was observed. The ratio became important for higher E. coli levels as an increase in microbial contamination of the second wash bath occurred, an increase and elevated levels in E. coli contamination of the end product were observed (occasionally numbers over 1000 cfu E. coli/g). The rinsing step on lettuce did not significantly reduce microbial contamination. The (Belgian) approach of tolerating “clean water” (but with a maximum of 3 log E. coli/100 ml) will not significantly affect microbial quality of the product. It also showed the need for potable water in the second washing bath to be debatable. Highly contaminated lettuce (4 log E. coli/g) affected microbial quality of washing baths unacceptable. Low level of sanitizer (1 ppm of chlorine, continuously monitored and stabilized) was, able to control the microbial quality of the water in washing baths to “clean”.
Keywords
wash water, cross-contamination, water quality, microbiology, Fresh produce, water management

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Citation

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MLA
Holvoet, Kevin, et al. “Potential Cross-Contamination of E. Coli between Lettuce and Wash Water Simulating an Industrial Fresh-Cut Lettuce Wash Process.” FoodMicro 2012, Abstracts, 2012, pp. 88–88.
APA
Holvoet, K., Sampers, I., Van Haute, S., Jacxsens, L., & Uyttendaele, M. (2012). Potential cross-contamination of E. coli between lettuce and wash water simulating an industrial fresh-cut lettuce wash process. FoodMicro 2012, Abstracts, 88–88.
Chicago author-date
Holvoet, Kevin, Imca Sampers, Sam Van Haute, Liesbeth Jacxsens, and Mieke Uyttendaele. 2012. “Potential Cross-Contamination of E. Coli between Lettuce and Wash Water Simulating an Industrial Fresh-Cut Lettuce Wash Process.” In FoodMicro 2012, Abstracts, 88–88.
Chicago author-date (all authors)
Holvoet, Kevin, Imca Sampers, Sam Van Haute, Liesbeth Jacxsens, and Mieke Uyttendaele. 2012. “Potential Cross-Contamination of E. Coli between Lettuce and Wash Water Simulating an Industrial Fresh-Cut Lettuce Wash Process.” In FoodMicro 2012, Abstracts, 88–88.
Vancouver
1.
Holvoet K, Sampers I, Van Haute S, Jacxsens L, Uyttendaele M. Potential cross-contamination of E. coli between lettuce and wash water simulating an industrial fresh-cut lettuce wash process. In: FoodMicro 2012, Abstracts. 2012. p. 88–88.
IEEE
[1]
K. Holvoet, I. Sampers, S. Van Haute, L. Jacxsens, and M. Uyttendaele, “Potential cross-contamination of E. coli between lettuce and wash water simulating an industrial fresh-cut lettuce wash process,” in FoodMicro 2012, Abstracts, Istanbul, Turkey, 2012, pp. 88–88.
@inproceedings{2983681,
  abstract     = {{The aim was to provide information about E. coli contamination of washing water to prevent water becoming a vehicle for transfer of microbial contamination to lettuce and to get insight on the factors affecting proper water management. A lettuce wash process was simulated to determine (1) the ability to use “clean” water and the tolerable E. coli levels for “clean” water and its’ potential to respect it upon re-use of water in the first washing bath, (2) the need and effect of using potable water in the second washing bath, (3) the use of a final rinsing step after washing to reduce the microbial contamination level of lettuce, (4) the influence of initial E. coli contamination levels of lettuce on the washing bath water quality and (5) the use of chlorine to control the water quality in the first washing bath (prevent cross-contamination of lettuce).
Due to transfer via drain water of washed lettuce, the contamination level of the “clean (re-used) water” in the first wash bath determined the contamination of the second wash bath (aimed to be potable water). For lower contaminations (<4 log E. coli/100 ml), the washing water did not transfer unacceptable levels of E. coli to the washed lettuce and no influence of the product/water ratio (kg/l) was observed. The ratio became important for higher E. coli levels as an increase in microbial contamination of the second wash bath occurred, an increase and elevated levels in E. coli contamination of the end product were observed (occasionally numbers over 1000 cfu E. coli/g). The rinsing step on lettuce did not significantly reduce microbial contamination. The (Belgian) approach of tolerating “clean water” (but with a maximum of 3 log E. coli/100 ml) will not significantly affect microbial quality of the product. It also showed the need for potable water in the second washing bath to be debatable. Highly contaminated lettuce (4 log E. coli/g) affected microbial quality of washing baths unacceptable. Low level of sanitizer (1 ppm of chlorine, continuously monitored and stabilized) was, able to control the microbial quality of the water in washing baths to “clean”.}},
  author       = {{Holvoet, Kevin and Sampers, Imca and Van Haute, Sam and Jacxsens, Liesbeth and Uyttendaele, Mieke}},
  booktitle    = {{FoodMicro 2012, Abstracts}},
  keywords     = {{wash water,cross-contamination,water quality,microbiology,Fresh produce,water management}},
  language     = {{eng}},
  location     = {{Istanbul, Turkey}},
  pages        = {{88--88}},
  title        = {{Potential cross-contamination of E. coli between lettuce and wash water simulating an industrial fresh-cut lettuce wash process}},
  year         = {{2012}},
}