Bacteriophages safely reduce<i>Salmonella</i>contamination in pet food and raw pet food ingredients

Abstract

Contamination of pet food with <i>Salmonella</i> is a serious public health concern, and several disease outbreaks have recently occurred due to human exposure to <i>Salmonella</i> tainted pet food. The problem is especially challenging for raw pet foods (which include raw meats, seafood, fruits, and vegetables). These foods are becoming increasingly popular because of their nutritional qualities, but they are also more difficult to maintain <i>Salmonella</i>-free because they lack heat-treatment. Among various methods examined to improve the safety of pet foods (including raw pet food), one intriguing approach is to use bacteriophages to specifically kill <i>Salmonella</i> serotypes. At least 2 phage preparations (SalmoFresh® and Salmonelex™) targeting <i>Salmonella</i> are already FDA cleared for commercial applications to improve the safety of human foods. However, similar preparations are not yet available for pet food applications. Here, we report the results of evaluating one such preparation (SalmoLyse®) in reducing <i>Salmonella</i> levels in various raw pet food ingredients (chicken, tuna, turkey, cantaloupe, and lettuce). Application of SalmoLyse® in low (ca. 2-4×10⁶ PFU/g) and standard (ca. 9×10⁶ PFU/g) concentrations significantly (<i>P</i> < 0.01) reduced (by 60-92%) <i>Salmonella</i> contamination in all raw foods examined compared to control treatments. When SalmoLyse®-treated (ca. 2×10⁷ PFU/g) dry pet food was fed to cats and dogs, it did not trigger any deleterious side effects in the pets. Our data suggest that the bacteriophage cocktail lytic for <i>Salmonella</i> can significantly and safely reduce <i>Salmonella</i> contamination in various raw pet food ingredients.