Last month, Dr. Nikki W. Shariat and Dr. Kristina M. Feye (along with their co-authors) published a groundbreaking paper in the Journal of Applied Microbiology on the use of CRISPR analysis to identify Salmonella serovars found in samples from commercial feed mills. Their two trials found that 15% and 9.1% of the feed mills studied tested positive for Salmonella — and the majority of the Salmonella serovars they found are known to cause human illness.
Their paper, “Incidence of Salmonella serovars isolated from commercial animal feed mills in the United States and serovar identification using CRISPR analysis,” clearly demonstrates that some of the Salmonella serovars that are most prevalent in processing plants are also found upstream in feed mills and are capable of surviving in feed.
The two trials discussed in the paper involved collection of feed samples from a total of 135 feed mills in 2018 and 2019. In the first trial, 15% of the feed mills were Salmonella positive, as were 9.1% of the feed mills in the second trial. In the course of their analysis, the researchers identified seven different Salmonella serovars in the feed samples, five of which are known to cause human illness. The most common were S. Infantis and S. Heidelberg, both of which have led to human Salmonella outbreaks and recalls linked to poultry in recent years. Three of the other serovars found (S. Reading, S. Typhimurium, and S. Braenderup) have also been linked to serious outbreaks of human illness.
The publishing of this paper should be an inflection point for the industry: We can no longer ignore the fact that there is a clear path for pathogens in animal feed to make their way into human foods, leading to human sickness, product recalls, and loss of life. The continually growing body of research on the role that feed and feed ingredients can play as a fomite for pathogens cannot be ignored.
As the authors note, this research “highlights the need to effectively mitigate pathogens in livestock and poultry feed.” Fortunately, effective feed sanitization tools make it possible to not only kill Salmonella at the point of contact, but to protect against recontamination until consumption.
Read Dr. Shariat and Dr. Feye’s full article here.