NONTHERMAL PLASMA SYSTEM FOR EXTENDING SHELF LIFE OF RAW BROILER BREAST FILLETS

A nonthermal dielectric barrier discharge (DBD) plasma system was modified and enhanced to treat broiler breast fillets (BBF) in order to improve the microbial quality of the meat. The system consisted of a high-voltage source and two parallel, round aluminum electrodes separated by three semi-rigid polypropylene barriers extending well beyond the electrodes. The broiler samples were packaged in sealed polyolefin plastic bags to allow for adequate gas volume in the package. A modified atmosphere (MA) blend of gas (65% O-2, 30% CO2, 5% N-2) was used to enhance the generation of reactive oxygen species during treatment. This research investigates the ability of this plasma system to extend the shelf life of BBF by reducing the number of spoilage bacteria. The system was tested on BBF and compared to triplicate untreated controls. Samples were treated outside the plasma generation field at ambient air temperature and pressure for 3 min at 75 kV and then stored at 4 degrees C. Surviving microbes were recovered on days 1, 3, 7, 10, and 14 via standard rinsing and plating on nutrient agar. There was a mean log reduction of 1.53 log(10) cfu mL(-1) after 24 h. After 14 days of storage, the treated samples had a mean population of 5.53 log(10) cfu mL(-1), which was 2.39 cfu mL(-1) lower than the control packaged in air and 1.52 log(10) cfu mL(-1) lower than the control packaged in MA. A level of 5.56 log(10) cfu mL(-1) falls below the generally accepted spoilage limit of 107 cfu mL(-1). Results demonstrate the ability of the nonthermal plasma system to reduce natural microflora on the surface of BBF and its applications in food safety and shelf life extension.