PhD defence

Battling microbes: disinfecting water during fresh-cut lettuce processing


Worldwide, chlorine is often used to disinfect the water during vegetable processing. However, some European countries are searching for alternatives. Until now, little is known about the practical effects of using alternative chemicals during vegetable washing. In her Ph.D. project, Jen Banach of Wageningen University & Research has been researching the impact of using alternative chemical water disinfection techniques during fresh-cut lettuce washing.

Her research showed that washing lettuce with disinfectants like chlorine dioxide and peracetic acid reduced the effect of harmful bacteria. However, how much these bacteria could be reduced was influenced by processing conditions like the dose of the disinfectant and the organic load and temperature of the water. In addition to doing lab and pilot-scale testing, Banach also investigated the effects of these alternatives from a broader perspective considering other criteria, besides the effectiveness of the disinfectant, in a multiple-criteria decision analysis. To this aim, peracetic acid was shown to be preferred by stakeholders to use to control the water during lettuce processing. This strategy appears to be the right balance between safety and effective water disinfection during lettuce washing.