Salmonella in feed

Salmonellosis is the common zoonotic disease, together with campylobacteriosis in the EU, and Salmonellla is a common cause of foodborne disease outbreaks (EFSA). In the EU, over 91,000 salmonellosis cases are reported each year. EFSA has estimated that the overall economic burden of human salmonellosis could be as high as €3 billion a year (EFSA). 79,698 cases were reported confirmed cases of human salmonellosis in the EU/EEA in 2018, by the most frequent serovars in 2018 (EFSA). The overall prevalence of Salmonella -positive units in animal – and vegetable-derived feed supplies in 2018 in the EU was 0,93% of 28,680 reported units. In compound feed (the finished feed for animals), the prevalence of Salmonella -positive units in 2018 was 0.52% of 10,497 tested samples for poultry. (EFSA One Health Zoonoses Report 2018). The control of Salmonella in animal feedstuffs is important to protect humans to be infected from contamination derived from infected animals. Feed is considered the most common source of Salmonella contamination for poultry flocks into commercial production situations (Jones & Richardson, 2004), its control and good management being important, ensuring a clean and safe production throughout the food chain, in order to avoid human infection by contamination derived from infected animals.

Nowadays, heat treatment is the most common to reduce Salmonella, but there is a high risk of recontamination due to the environmental contamination of feed mills, mainly during the cooling and drying process, but also during transportation and storage by cross contamination. Furthermore, it is a bacterium capable of forming biofilm on different surfaces, becoming a source of contamination in feed in different production lines. Therefore, we must apply additional measures in the fight against Salmonella.

Another factor associated with Salmonella contamination is the Enterobacteriaceae count (Jones, 2011), its presence being observed at levels higher than 10,000 cfu / g of Enterobacteriaceae in unprocessed feed and 100 cfu / g in processed feed (Jones and Richardson, 2004). Dust is also related to Salmonella counts (Haggblom, 1994; Jones and Richardson, 2004), which highlights the importance of its control in feed mills. High levels of Salmonella can affect not only feed quality and animal performance, but also the reputation of the farm. Therefore, we must consider various measures to reduce or eliminate it in feed mills, including improving hygiene through a good cleaning and disinfection plan, the use of organic acids or other chemical preservatives for feed, heat treatment or the use of feed additives to modulate the intestinal microbiota.