Contamination and Animal Feed

Dioxins: ­Polychlorinated byphenyls (PCBs) or dioxins, many considered to be carcinogens when fed for extended periods, have been identified as a potentially hazardous risk for animal feed. In 1997, FDA found contamination of animal feeds with dioxin, which resulted in elevated levels of dioxin in chickens, eggs, and catfish. The source of the dioxin contamination was traced to a mined clay product called “ball clay,” which is used as an anticaking agent in soybean meal, other feed components, and complete animal feeds. As ball clay in this episode was an occasional ingredient, the industry and ball clay suppliers asked for its removal from the Association of American Feed Control Officials’ Official Publication, thereby precluding its use again, as state law utilizes that publication as the official list of approved ingredients.

Currently, there are no regulatory tolerances or action levels for dioxins or PCBs in animal feed. PCBs have become a persistent and omnipresent contaminant in the environment. As a result, certain animal feeds, principally those of marine origin, may contain PCBs at low levels. Nonetheless, feed manufacturers work with suppliers to ensure the potential risk is controlled.

Formulation: With most animal feeds provided as a complete diet, formulation of finished products is important to ensure the proper nutritional levels are supplied for the specific type of animal and life stage. It is important deficiencies or toxicities are avoided when formulating. Review of mixing records, proper mixing times, and testing of finished product are examples of the steps feed manufacturers take to ensure finished products meet expected specifications. Proper controls of manufacturing processes ensure finished products meet the desired specifications. Feed manufacturers must identify areas that are critical processes, and establish steps that ensure the safety of finished products.

Biological. Microbiological contamination of pet food is a human food safety risk due to the pet food feeding practices and potential exposure to people. In 2012, CDC reported that a multistate outbreak of Salmonella Infantis infections was linked to pet food. More than 20 people across 13 states were infected. The association between human outbreaks of salmonellosis and contact with Salmonella-contaminated pet food and pet treats is well established. FDA launched several pet food sampling programs in the past few years, but the most recent results from 2012 to evaluate the prevalence of Salmonella in pet food are still pending.

Due to the potential hazards from microbiological contamination, pet food manufacturers must take steps to control the risk. This is done through manufacturing processes (segregation of manufacturing areas; stringent sanitation practices; personal flow), environmental monitoring, finished product testing (hold and release), and supplier verification programs. While such preventive controls are expensive, the potential severity and exposure of the hazard require it.

Biosecurity: For livestock feeds, microbiological contamination generally is not considered a human safety risk due to the feeding practices of animals and the lack of animal feed exposure to humans that could create a food safety risk. However, feed manufactures must control the potential risk for the spread of disease among livestock. As an example, feed manufacturers must establish stringent biosecurity practices to prevent the spread of Porcine Epidemic Diarrhea virus (PEDv) to pigs. This includes steps during manufacturing and transport to ensure the feed or transport vehicles are not contaminated from one farm to the next.

Moreover, FDA’s Compliance Policy Guide (690.800) entitled “Salmonella in Food for Animals” details eight serotypes of salmonellae in five species of feed that must be controlled. Otherwise, FDA says the feed may be deemed to adulterated and subject to recall if these salmonellae are discovered.