FEED SAFETY ▶▶▶


Reducing the risk of salmonella re- contamination in feed


Deploying risk mitigation strategies across the feed-to-food production chain can help assure safe animal feed and poultry production. However, certain processes, such as the desiccation (drying out) of salmonella cells, can circumvent routine cleaning and hygiene practices.


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5,00,000 Detrimental effects 0 Whole corn 26 Ground corn Whole wheat Whole wheat ▶ POULTRY WORLD | No. 2, 2020


If micro-organisms succeed in accessing nutrients during the grinding process, nutrient degradation will occur,


BY GEERT VAN HOUTE, GLOBAL PROGRAMME MANAGER FEED SAFETY


uring certain phases of feed production, salmo- nella cells may become dormant only to re-acti- vate later in the production process. The inability to detect dormant salmonella cells may under-


mine routine hygiene checks and threaten feed safety. This risk demands strategies that go beyond hydrothermal treat- ment. Research has shown that preservation strategies, in- cluding the application of potent buffered and synergistic blends of organic acids and surfactants, can significantly re- duce contamination risk during animal feed processing. Feed contamination can occur at any stage of poultry pro- duction, including in raw materials, transport, warehousing, processing, or even bird housing. Each stage presents its own risks. For example, mitigation of microbial risks is nec- essary in the early stages of the feed-to-food chain to avoid


Figure 1 - Rapid increase of enterobacteria due to grinding Quick increase of Enterobacteria due to grinding


cross-contamination and ensure safe food for human con- sumption. Later in the production process, operation hy- giene, storage protocols and good on-farm management practices are other critical points where microbial contamination could occur. When the conditions for microbial growth are present at any stage of the feed chain, Enterobacteriaceae like salmonella can threaten both animals consuming contaminated feed and humans consuming the animal-based product. Such a threat is dormant salmonella caused by desiccation. This ‘drying out’ process can enable salmonella to remain un- detected during routine checks and lead to a wrongful con- clusion that feed materials and production lines are free from salmonella.


Re-contamination risk


Increasing temperature and humidity can activate dormant salmonella and other Enterobacteriaceae. Temperature and humidity variations can present a risk at any stage of the pro- duction process, including raw material storage, grinding and production stops; allowing for the metabolism of dormant salmonella and other micro-organisms to reactivate and proliferate. Increases in temperature and humidity can enable nutrients to become accessible during the grinding process; effectively opening up a point of access for micro- organisms to enter, multiply and cross-contaminate feed production processes. Figure 1 shows the increase in the Enterobacteriaceae colony-forming unit load at the pre and post-grinding stages.


PHOTO: JAN WILLEM VAN VLIET


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