USDA Agriculture Research Service scientists have found that a common water-borne protozoa protects Salmonella from lethal chemical treatments such as calcium hypohlorite. This finding could explain why some processing plant sanitation programs fail.

The ARS researchers, led by microbiologist Maria Brandl, observed that a common, water-borne protozoa known as a tetrahymena consumes live Salmonella that it encounters in the environment, reported. However, the tetrahymena cannot digest the bacteria and expels it encased in miniature pouches called food vacuoles. The encounter enhances Salmonella survival during sanitation procedures.

The data could lead to the development of new, more powerful, but more environment-friendly ways to reduce the incidence of bacteria pathogens in food. Brandl is now attempting to pinpoint genes that Salmonella bacteria turn on while inside the vacuoles.