Date Full Report Received08/14/2015
Date Abstract Report Received08/14/2015
InvestigationInstitution: Kansas State University
Primary Investigator: Jason Woodworth
Co-Investigators: Michael Tokach, S.S. Dritz, Phil Gauger, Jianqiang Zhang, Cassandra Jones, Rodger Main, Charles Stark, Roger Cochrane, Loni Schumache
Funded ByNational Pork Board
The contamination of feed and feed ingredients with Porcine Epidemic Diarrhea Virus (PEDV) is a major concern to the swine industry and knowing feed or feed ingredients can support PEDV transfer, feed mills have become a potential source of cross contamination. This study aimed to utilize the only known pilot feed mill facility approved for pathogenic feed agent use in the United States to 1) determine if sequencing feed batches could minimize the risk of PEDV cross-contamination; 2) evaluate the effect of conditioning PEDV-contaminated feed below traditional pelleting temperatures on PEDV infectivity as measured by PCR and bioassay; and 3) evaluate the effect of manufacturing PEDV-contaminated feed on subsequent feed mill environmental surface contamination. The results suggest feed batch sequencing can reduce the concentration of PEDV genetic material in feed; however, feed can still be infectious and environmental surfaces, including equipment, remain contaminated. Pigs challenged with feed conditioned at less than 130°F resulted in PEDV infection. While these temperatures are below typical conditioning temperatures, feed is frequently manufactured below optimal temperatures at times during the feed manufacturing process, such as during start-up or resolution of a pellet mill plug. This contaminated pelleted feed could then lead to cross-contamination in the cooler or grain handling equipment; potentially infecting PEDV-free feed. All sampled feed mill surfaces were contaminated with PEDV RNA after production of the positive treatment and remained contaminated after batches of feed. Since the virus was ubiquitous, decontamination of the facility proved challenging and required dry physical cleaning, wet chemical cleaning, and dry heat for complete decontamination. Proper decontamination in a large-scale commercial feed mill would be nearly impossible and therefore it is important to prevent the entry of PEDV contamination into the mill. This research helps raise awareness about the impact of producing PEDV-contaminated feed in a mill, the importance of feed mill biosecurity, and potential mitigation solutions to reduce the risk of infectivity of PEDV in animal feed.