Led by ARS microbiologist Mark Berrang, a research team conducted tests for the presence of Listeria in a brand new commercial cooking facility before and after processing began. Starting with a clean slate made it easy to track sources of contamination for the team from the Bacterial Epidemiology and Antimicrobial Research Unit at the agency’s RichardB.RussellResearchCenter in Athens, GA.
Potential sources of Listeria were tested by taking samples of soil and water around and near the plant’s exterior, and by testing heavily-traveled floor surfaces following personnel shift changes. In addition, samples were collected and tested from incoming air vent filters and from monthly swabs of incoming raw meat. The facility was free of Listeria when it was first built. Floor drains in the plant were sampled monthly to determine when the plant would become colonized with Listeria.