Characterizing the rapid spread of porcine epidemic diarrhea virus (PEDV) through an animal food manufacturing facility

PLOS ONE, Nov 2019

New regulatory and consumer demands highlight the importance of animal feed as a part of our national food safety system. Porcine epidemic diarrhea virus (PEDV) is the first viral pathogen confirmed to be widely transmissible in animal food. Because the potential for viral contamination in animal food is not well characterized, the objectives of this study were to 1) observe the magnitude of virus contamination in an animal food manufacturing facility, and 2) investigate a proposed method, feed sequencing, to decrease virus decontamination on animal food-contact surfaces. A U.S. virulent PEDV isolate was used to inoculate 50 kg swine feed, which was mixed, conveyed, and discharged into bags using pilot-scale feed manufacturing equipment. Surfaces were swabbed and analyzed for the presence of PEDV RNA by quantitative real-time polymerase chain reaction (qPCR). Environmental swabs indicated complete contamination of animal food-contact surfaces (0/40 vs. 48/48, positive baseline samples/total baseline samples, positive subsequent samples/total subsequent samples, respectively; P < 0.05) and near complete contamination of non-animal food-contact surfaces (0/24 vs. 16/18, positive baseline samples/total baseline samples, positive subsequent samples/total subsequent samples, respectively; P < 0.05). Flushing animal food-contact surfaces with low-risk feed is commonly used to reduce cross-contamination in animal feed manufacturing. Thus, four subsequent 50 kg batches of virus-free swine feed were manufactured using the same system to test its impact on decontaminating animal food-contact surfaces. Even after 4 subsequent sequences, animal food-contact surfaces retained viral RNA (28/33 positive samples/total samples), with conveying system being more contaminated than the mixer. A bioassay to test infectivity of dust from animal food-contact surfaces failed to produce infectivity. This study demonstrates the potential widespread viral contamination of surfaces in an animal food manufacturing facility and the difficulty of removing contamination using conventional feed sequencing, which underscores the importance for preventing viruses from entering and contaminating such facilities.

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Characterizing the rapid spread of porcine epidemic diarrhea virus (PEDV) through an animal food manufacturing facility

November Characterizing the rapid spread of porcine epidemic diarrhea virus (PEDV) through an animal food manufacturing facility Loni L. Schumacher 0 1 2 Anne R. Huss 0 2 Roger A. Cochrane 0 2 Charles R. Stark 0 2 Jason C. Woodworth 0 2 Jianfa Bai 0 1 2 Elizabeth G. Poulsen 0 1 2 Qi Chen 0 2 Rodger G. Main 0 2 Jianqiang Zhang 0 2 Phillip C. Gauger 0 2 Alejandro Ramirez 0 2 Rachel J. Derscheid 0 2 Drew M. Magstadt 0 2 Steve S. Dritz 0 1 2 Cassandra K. Jones 0 2 0 Current address: BioMatrix International , Princeton, Minnesota , United States of America 1 Department of Diagnostic Medicine/Pathobiology, Kansas State University , Manhattan , Kansas, United States of America, 2 Department of Grain Science and Industry, Kansas State University , Manhattan , Kansas, United States of America, 3 Department of Animal Sciences and Industry, Kansas State University , Manhattan , Kansas, United States of America, 4 Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University , Ames, Iowa , United States of America 2 Editor: Yongchang Cao, Sun Yat-Sen University , CHINA New regulatory and consumer demands highlight the importance of animal feed as a part of our national food safety system. Porcine epidemic diarrhea virus (PEDV) is the first viral pathogen confirmed to be widely transmissible in animal food. Because the potential for viral contamination in animal food is not well characterized, the objectives of this study were to 1) observe the magnitude of virus contamination in an animal food manufacturing facility, and 2) investigate a proposed method, feed sequencing, to decrease virus decontamination on animal food-contact surfaces. A U.S. virulent PEDV isolate was used to inoculate 50 kg swine feed, which was mixed, conveyed, and discharged into bags using pilot-scale feed manufacturing equipment. Surfaces were swabbed and analyzed for the presence of PEDV RNA by quantitative real-time polymerase chain reaction (qPCR). Environmental swabs indicated complete contamination of animal food-contact surfaces (0/40 vs. 48/48, positive baseline samples/total baseline samples, positive subsequent samples/total subsequent samples, respectively; P < 0.05) and near complete contamination of non-animal food-contact surfaces (0/24 vs. 16/18, positive baseline samples/total baseline samples, positive subsequent samples/total subsequent samples, respectively; P < 0.05). Flushing animal food-contact surfaces with low-risk feed is commonly used to reduce cross-contamination in animal feed manufacturing. Thus, four subsequent 50 kg batches of virus-free swine feed were manufactured using the same system to test its impact on decontaminating animal food-contact surfaces. Even after 4 subsequent sequences, animal food-contact surfaces retained viral RNA (28/33 positive samples/total samples), with conveying system being more contaminated than the mixer. A bioassay to test infectivity of dust from animal foodcontact surfaces failed to produce infectivity. This study demonstrates the potential widespread viral contamination of surfaces in an animal food manufacturing facility and the - Data Availability Statement: All relevant data are within the paper. Funding: This work was supported by the National Pork Board to JCW, 14-273. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing interests: The authors have declared that no competing interests exist. difficulty of removing contamination using conventional feed sequencing, which underscores the importance for preventing viruses from entering and contaminating such facilities. Introduction Federal regulations recognize animal feed as food and an important part of our national food supply. Recent changes in legislation through the Food Safety Modernization Act, along with evolving consumer demands, are placing greater emphasis on the role of animal food in the farm-to-fork food safety system [ 1 ]. Recently, porcine epidemic diarrhea virus (PEDV), a swine pathogen present in other parts of the world, was identified for the first time in the United States [ 2, 3 ]. The introduction of PEDV into U.S. herds was remarkable because of the sheer magnitude of infectivity and impact on animal health and welfare [ 4, 5 ]. Nonetheless, it was also significant because PEDV is one of the first viral pathogens confirmed transmissible in animal food. In one proof-of-concept study, suspected particulates of animal food and dust was found infectious [ 6 ]. Potential routes of viral introduction into the animal food manufacturing process have been identified [ 7 ]. Therefore, there is potential for viral contamination of animal food manufacturing facilities [ 8 ]. However, there is no available data describing the transmission of viruses in either animal or human food manufacturing facilities, nor are there established procedures to reduce or eliminate viral contamination on f (...truncated)


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Loni L. Schumacher, Anne R. Huss, Roger A. Cochrane, Charles R. Stark, Jason C. Woodworth, Jianfa Bai, Elizabeth G. Poulsen, Qi Chen, Rodger G. Main, Jianqiang Zhang, Phillip C. Gauger, Alejandro Ramirez, Rachel J. Derscheid, Drew M. Magstadt, Steve S. Dritz, Cassandra K. Jones. Characterizing the rapid spread of porcine epidemic diarrhea virus (PEDV) through an animal food manufacturing facility, PLOS ONE, 2017, Volume 12, Issue 11, DOI: 10.1371/journal.pone.0187309