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Current technologies to control pathogens in feed
Animal feed has been identified as a vector for bacteria that are harmful to human and animal health. A majority of the research has been focused on Salmonella and human food safety. However, other species of bacteria in feed, such as E. coli and Clostridia, negatively affect the intestinal health of the animal. This can result in reduced animal performance and economic loss to the producer. Control measures for reducing bacterial contamination of feed include preventing contamination from entering the facility, preventing multiplication of contaminants within the facility, and implementing processes that reduce the initial level of bacteria in feed and protect the feed from recontamination. Feed ingredients continue to be a source of entry for bacteria into a facility. Implementing a routine monitoring program of incoming ingredients and vendor approval process can reduce risk. Companies should verify that detection methods for bacterial contaminants are suitable for the ingredient being evaluated. Recent research has shown that utilizing methods that have been developed for human foods can often fail to detect pathogens in feed, such as Salmonella. In the mill, dust and residues within the transport system are the primary sources of contamination. Dust can contain as much as 1000 cfu/g of Salmonella and >100,000 cfu/g of enterobacteriaceae. Properly operating dust collection systems are considered essential in reducing persistent contamination of the facility. Residue formation within a transport system indicates moisture penetration (i.e., a leak) or condensation and promotes bacterial multiplication. Processes that have been employed to reduce bacteria involve thermal treatment and chemical preservatives or a combination of both. However, numerous factors can influence the effectiveness of these intervention strategies. Contamination of feed by Salmonella subsequent to thermal treatment has been observed within transport systems, in storage bins and in feed trucks via dust and residues. This recontamination is not limited to Salmonella, as it also occurs with other economically-important contaminants including Clostridia, enterobacteriaceae and mold. As a result, chemical preservatives such as organic acids and formaldehyde have been utilized to protect feed from this risk. Controlling pathogens in feed is a challenging, but critically important, part of feed manufacturing. It requires a multifaceted approach, as each control point has its challenges. Because the variety of organisms causing contamination can vary greatly, is it recommended that multiple methods be employed to provide the most effective level of protection.
Keywords: food/feed safety, intestinal health, pelleting, chemical preservatives