Microbial pathogen contamination of animal feed

Animal feed production is a complex process involving several steps during feed milling. In feed manufacturing, there are numerous opportunities to introduce microorganisms from various environmental and other sources. While most of these microorganisms are likely nonpathogenic, pathogens can also be members of feed microbial populations. In addition to fungi, several bacterial pathogens have been identified. They are believed to be associated with animal feed and include Listeria, Clostridia, pathogenic Escherichia coli, and Salmonella, as well as others that are less well characterized. Of the pathogens known to contaminate animal feeds, Salmonella has probably been the most extensively characterized. Much of the focus has been on designing intervention strategies to reduce Salmonella population levels on feeds. In this chapter, a survey of some of the pathogens found in feeds will be discussed, along with sources of feed microbial contamination, and finally future directions for applying molecular technologies such as microbiome sequencing to characterize feed microbial communities.