15 March 2022 – There are numerous Salmonella entry points in the poultry production process, presenting a number of vulnerabilities for the industry to address in order to control contamination. Understanding which ones carry a higher risk can help producers implement mitigation strategies at points that have the most significant impact.
Feed as a fomite for microbial contamination is sometimes overlooked but can be one of the key intervention points in the fight against Salmonella. As Anitox’s Enrique Montiel, the company’s Global Director of Nutrition and Live Production explained to Feedinfo in a recent sit-down, feed carries a Salmonella risk as independent raw materials being brought into mills from multiple sources and as complete feeds being transported and fed to livestock.
In this Industry Perspectives, we take a closer look at the points in the feed production process that could help the poultry industry’s mitigation efforts and discuss the feed ingredients of major concern for Salmonella contamination. We also look at the economic impact that contamination can have on processing and production facilities and how Anitox is making itself available to support these producers in delivering clean feed.
[Feedinfo] How important an entry point is feed for Salmonella in the poultry production process compared to others like housing, litter, transportation, etc.? Is there reason for concern here?
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[Enrique Montiel] Feed is the most widespread and impactful fomite within poultry production and as a complex matrix can sustain a diverse microbial load for variable periods of time. Contamination within feed can begin as a single contaminated ingredient and turn into multiple batches of contaminated feed that get distributed to millions of birds. Fomites such as litter and rodents, which could be associated with a higher pathogen load, are limited to a poultry house and are time specific. For example, litter is present throughout the entire duration of the flock, but it does not start as a highly contaminated fomite. It becomes that way through use. Feed is omnipresent throughout poultry production. |
Enrique MontielThe dynamic nature of feed manufacturing involves multiple raw materials from various geographies which increases the chances for microbial contamination to occur. Feed enters every house and is consumed by every bird, every day. The frequency of which this fomite is supplied, combined with the variation in microbial loads from one batch to another, contributes to feed’s efficacy as a fomite for pathogens. It contaminates poultry houses from the moment it is supplied until the bird excretes it as waste.
[Feedinfo] How aware do you think poultry producers are of feed as fomite? Is there more sector education that needs to be done around this subject?
[Enrique Montiel] Industry bodies and producers are more aware of feed as a fomite than ever, largely due the growing number of research studies related to Salmonella in animal feeds and the inclusion of feed in biosecurity guidelines. For example, the USDA released biosecurity guidelines and suggestions to help producers avoid introducing Avian Influenza (AI) into their facilities that focus heavily on protecting feed from contamination.
However, the industry still seeks to better understand how feed can impact Salmonella prevalence within live production. Throughout the industry, there are misconceptions as to what constitutes an effective feed pathogen control tool. Many producers take proactive measures to manage feed as a fomite but do not realise that their tools do not effectively protect feed from recontamination. For effective feed pathogen control, the tool needs to reduce the microbial load and continue to protect feed until the point of consumption.
As an industry, we also need to thoroughly understand how we determine the effectiveness of the tools we use. Feed is a complex matrix to assess for pathogens such as Campylobacter and Salmonella. The methods we use need to withstand the challenges that feed presents while also recovering pathogens from feed effectively. This is something Anitox has dedicated many of our efforts to. The only way to truly understand how well our interventions work is to use and develop methods that improve our pathogen detection sensitivity. Tools such as CRISPR will be critical to understanding the prevalence of feed pathogens throughout the feed production cycle.
[Feedinfo] So what are the feed ingredient(s) of major concern for Salmonella contamination? Why is that the case?
[Enrique Montiel] Vegetable and animal proteins are considered high-risk ingredients for Salmonella contamination. According to several pieces of literature and results from Anitox's routine feed monitoring programme, ingredients such as oilseed meals, wheat and corn have been linked to Salmonella incidences of 3-8%, 1% and 9%, respectively.
Producers need to understand the risk associated with the feed ingredients they are using as it helps determine the best course of action for feed pathogen control. For example, a study examining one year's worth of soybean samples for Salmonella found an incidence rate of 14.6%. While this may seem high, it is important to note that Salmonella incidence within ingredients is dependent on growing seasons and regions, both of which can cause a great degree of variability. We can implement control measures in many areas, including ingredient processing or compound feed mixing. Suppose an operations risk of Salmonella is primarily due to a single high-risk ingredient. Producers can, in this case, handle or implement more stringent testing and/or treatment standards for that ingredient to protect the mill from contamination. A major key to reducing feed contamination is recognising the risk level and implementing control measures where they are most impactful. It is also important to note that throughout the feed production chain feed can become recontaminated.
[Feedinfo] So where is this recontamination happening most often in the feed production process? We know about Salmonella transmission occurring through incoming feed ingredients, but are there other points we should be focussing intervention efforts on too?
[Enrique Montiel] One well-understood route of Salmonella transmission to poultry production occurs through feed and feed ingredients, however, it is easy to overlook the transmission that occurs throughout the feed production chain. A study on Salmonella in commercially manufactured feeds found Salmonella and Enterobacteriaceae contamination in dust collected throughout the mill, specifically at ingredient receiving, the mixer, the pellet mill and the cooler. This demonstrates that Salmonella contamination does not just come from ingredients, but also occurs within the feed milling or ingredient processing environment.
Anytime raw ingredients enter a feed mill or processing facility, they potentially introduce contamination and engineering controls such as heat, which already plays a significant role in the production of pelleted feeds and oilseed processing, can help reduce the microbial load within feed. However, we know that post-heating feed and ingredient products are vulnerable to recontamination. For example, in oilseed processing, we primarily see recontamination occurring due to system contamination through a failure to heat all of the product thoroughly, the protection of Salmonella with oil residues within the system, or dust movement into areas such as the cooler.
Aside from treating product with a feed sanitiser that protects against Salmonella recontamination, ingredients processing and feed milling facilities have the option to reduce Salmonella residences within the system by flushing the production equipment with highly treated feed material on a regular basis. Preventative flushes with sanitised feed or raw materials reduce the load and prevalence of Salmonella within the facility and help prevent Salmonella-free materials from becoming recontaminated. Every feed production stage deals with Salmonella challenges and it is crucial to understand how Salmonella and other feed pathogens behave within individual production environments to implement effective feed pathogen control and reduce pathogen introduction into live production.
[Feedinfo] Once contamination has been identified, how can this impact operations? What is the economic cost of correcting it?
[Enrique Montiel] Contamination can impact facilities differently, but the end result is usually the same. Salmonella recontamination of feed and feed ingredients within feed mills and ingredient processing facilities reduces facility productivity, leads to decontamination and maintenance costs, and results in reputational damage.
Some countries regulate based on suppliers providing proof of Salmonella-free ingredients, in which case the burden of cost for Salmonella contamination falls on the ingredient processor. In countries and operations where this is not the case, cost burden falls on the poultry producer. Poultry pathogen prevalence in feed can result in productivity issues such as increased poultry disease and mortality, poor flock uniformity as well as poor persistency and eggshell quality in commercial layers and parent stock. For example, a single enteritis event in a commercial layer can result in a loss of 6 eggs over an entire lifetime. If this were to occur in a 2 million-bird flock, it could cost a producer approximately $1.3 million.
Salmonellosis in humans attributed to poultry impacts the entire industry. We all understand that the consumer's proper cooking and handling of poultry products is very important to avoid Salmonella infections in humans, but once the product is sold, we don't control what happens. To protect our industry, we must implement pathogen control programmes to help reduce the likelihood that the end product bears a level of contamination capable of causing an outbreak.
[Feedinfo] How has Anitox committed itself to tackling the problem of Salmonella contamination in oilseeds? And how successful have these efforts been?
[Enrique Montiel] Anitox has evaluated feed pathogen control usage to create custom treatment programmes that suit producer needs for more than 40 years. Our highly qualified team works with producers throughout the entire feed production chain to ensure that feed remains clean until the point of consumption. Our research and development team concentrates on the efficacy of our products and our ability to assess feed for food-borne pathogens accurately. We are the clean feed experts because we understand how feed behaves as a fomite and how pathogens behave in feed.
Additionally, collaborative projects with key research laboratories worldwide have proven our feed sanitation offerings to effectively control feed pathogens such as Salmonella and protect against recontamination for upward of 14 days at low inclusion rates. For example, our feed sanitiser Finio was shown to provide effective Salmonella control at 1 kg/MT in a study performed by the Animal Plant and Health Agency (APHA). Anitox recommends an inclusion rate of 2 kg/MT to provide continuous Salmonella control in feed up to the point of consumption.
Published in association with Anitox