The use of naturally fermented cheese whey may be as effective as chlorine for reducing pathogens in lettuce.
That’s the finding of research conducted at the Universidade de Lisboa in Lisbon, Portugal and published in Foodborne Pathogens and Disease, “Preliminary study on the effect of fermented cheese whey on Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella Goldcoast populations inoculated onto fresh organic lettuce.”
While chlorine has been the sanitizer most used in the produce industry to ensure safety of lettuce and salads, concerns about environmental and consumers’ health risk from the formation of chlorine carcinogenic toxic derivatives led researchers to study new methodologies that can simultaneously reduce pathogens and toxic chemicals, according to the report.
Researchers examined cheese whey fermented by an industrial starter consortium of lactic acid bacteria for its antibacterial capacity to control a selection of pathogenic bacteria, pathogens common to produce safety outbreaks.
Organically grown lettuce was inoculated and was left for about an hour in a safety cabinet before washing with a perceptual solution of fermented whey in water for durations of 1 minute and 10 minutes.
Cells of pathogens recovered were counted and compared with that obtained for a similar treatment using a chlorine solution.
Results show that both treatments were able to significantly reduce the number of bacteria in a range of 1.15–2 and 1.59–2.34 colony forming units per gram.
The study may help as a nontoxic alternative to chemicals such as chloride in controlling the growth of pathogenic bacteria that cause outbreaks, said Maria Ferreira, a researcher in the microbiology laboratory in the university’s Department of Natural Resources, Environment and Territory.
Ferreira said researchers plan to work on the scaling up of the process or continue with alternative product applications.
“Fermented whey is a promising natural product that can be a good alternative to the use of chlorine in fresh vegetable disinfection,” she wrote in the study. “This was a preliminary study with important outcomes, which open novel cost-effective and health-promoting perspectives in the disinfection of minimally processed salads, using fermented whey, but being a preliminary result, further work should be done to test additional strains of each bacteria used as well as other pathogenic bacteria and different exposure times.”