For the first experiment, 5 different feed manufacturing surfaces and 10 sanitizing treatments were evaluated Surfaces included stainless steel, plastic, rubber, woven polypropylene tote bag, and sealed concrete, which were evaluated by applying PED virus, followed by application of the various sanitizing agents. Quantification of detectible genetic material collected via surface swab was then performed using real time, reverse transcriptase polymerase chain reaction (qRT-PCR). Liquid Sal CURB and liquid bleach were the most effective chemical treatments to reduce the quantity of detectable PEDV RNA, but the practicality of their application in field settings is limited due to their liquid state and potential corrosiveness.
For Experiment 2, medium chain fatty acids (MCFA) and formaldehyde were used to treat rice hulls to disinfect laboratory-scale mixers and a production scale mixer and bucket elevator system. Overall, the use of rice hull flushes effectively reduced the quantity of detectable RNA present after mixing a batch of PEDV-positive feed. Chemical treatment of rice hulls with formaldehyde and 10% MCFA provided additional reduction in detectable RNA. Finally, dust collected after manufacturing PEDV-inoculated feed contains a very high quantity of viral RNA and was found infective, demonstrating it has the potential to serve as a vector for PEDV transmission.
Differences in surface structure and porosity affect the ability of chemical disinfection agents to inactivate and remove genetic material
Liquid disinfectants including formaldehyde and sodium hypochlorite (bleach) appear to be efficacious PEDV surface disinfection agents; however, practicality of use and safety in feed manufacturing facilities need to be considered.
Using abrasive agents (i.e. rice hulls) reduces cross contamination and treatment of the rice hulls with formaldehyde or MCFA can further reduce risk for manufacturing feed where wet cleaning methods cannot be easily applied.
Dust can contain a high quantity of PEDV genetic material that can cause infectivity and therefore be a vector for PEDV transfer.
Kansas State University
Dept. of Animal Sciences & Industry
251 Weber Hall
Manhattan, KS 66506