Drawing on co-principal investigators’ expertise and industry contacts in Washington State and the Midwest, the research will include experiments at small-, medium- and large-scale packing facilities.
The co-PIs are Umut Yucel, Ph.D., K-State; Faith Critzer, Ph.D., University of Georgia and formerly with Washington State University; Manreet Bhullar, Ph.D, K-State; and Londa Nwadike, Ph.D, University of Missouri.
The research involves both laboratory experiments and field trials. During the lab phase, Trinetta cut coupons, or discs, from used plastic and wood harvest bins and nylon picking bags. She inoculated them with known amounts of Salmonella, Listeria monocytogenes or Shiga toxin-producing E. coli. The organisms were either part of biofilms or in the sessile stage.
The coupons were then exposed to one of five commercial sanitizers — chlorine, chlorine dioxide gas, peracid (peracetic acid), steam or silver dihydrogen citrate — and incubated for two, 24 or 96 hours.
After each treatment, Trinetta measured the number of organisms recovered. Although she is still reviewing data, she said some trends already are apparent.
“I don’t have the final statistics, but I can tell you that wood is very difficult to clean, and plastic is the surface that is the easiest to clean,” Trinetta said. “Chlorine dioxide gas has been giving us good results.”
Based on the lab results, she will whittle the sanitizers down in number for the next step of testing.
It will involve trials at two packinghouses in Washington State and two in the Midwest in early summer. Unlike the lab trials, Trinetta said they will use surrogate organisms that behave similarly to the pathogens but are safe for humans.
The researchers plan to inoculate bins and picking bags previously used by the packing facilities but are past their usefulness. Then they will sanitize the containers under packinghouse conditions and measure the number of organisms they can recover.
Trinetta also praised the industry for providing input into the project and for helping guide the researchers.
“I think it was very important to try to understand what the industry was open to eventually try,” she said. “I could come up with bacteriophage application, for example, but is it really applicable in a production location?”