Practical Strategies to Maintain Feed Safety

While the U.S. feed supply is the safest in the world, there is still opportunity for improvement. Some practical methods to improve feed safety include: 1) prioritizing ingredient safety; 2) controlling dust and traffic; and 3) strategically utilizing mitigants. First, feed manufacturers must not compromise on ingredient safety. Once present, hazards such as mycotoxins and biological pathogens cannot be easily eliminated. Contaminated feed played a pivotal role in the spread of porcine epidemic diarrhea virus (PEDV) in 2013 to 2014 (Bowman et al., 2015). Recently, Dee et al. (2017, 2018) demonstrated common feed ingredients can be vectors for transboundary diseases. In these cases, exclusion of the pathogen should be the priority strategy to prevent foreign animal disease entry into the U.S. through feed ingredients. Second, facilities must control dust and traffic flow. In a survey of 11 different feed mills producing livestock feed, Boccatto et al. (2017) found that swabs of the ingredient pit, floors, and worker shoes had the greatest prevalence of Salmonella spp. of all mill locations tested (8 to 16% positive rate). Biological hazards be spread by dust to feed mill surfaces. Huss et al. (2016) demonstrated that manufacturing feed with a Salmonella spp.-contaminated ingredient increased (P<0.05) the number of Salmonella spp.-positive feed mill surfaces from 10% to over 40%. Similarly, Schumacher et al. (2017) demonstrated that introducing PEDV into a mixer resulted in an increase (P<0.05) of PEDV-contaminated feed mill surfaces from 0 to over 90%. Gebhardt et al. (2017) later demonstrated that dust collected from these surfaces was capable of causing PEDV infection. Regardless if surfaces were contaminated with Salmonella spp. or PEDV-contaminated, liquid cleaning and sanitizing was needed to fully eliminate pathogens from surfaces. Finally, facilities should strategically use mitigation to further reduce risk of feed safety hazards. Yoder et al (2018) demonstrated that cleaning mycotoxin-contaminated corn reduced (P<0.05) aflatoxin by 26% and fumonisin by 45%. However, this resulted high contamination in screenings. Cochrane et al. (2015, 2016) showed that pelleting reduced (P<0.05) Salmonella spp. and PEDV, but care must be taken to not re-contaminate feed during cooling or transport. Finally, chemical additives, such as formaldehyde-type products and medium chain fatty acids reduce (P<0.05) the risk of bacteria and PEDV, but some have additional worker safety and logistical concerns. In summary, the U.S. feed supply is extremely safe, but feed mills should take proactive approaches to maintain these high standards of safety.