Optimization of in-package cold plasma treatment conditions for raw chicken breast meat with response surface methodology
Hong Zhuanga, Michael J.RothrockJra, John E.Linea, Kurt C.Lawrencea, Gary R.Gamblea, Brian C.Bowkera, Kevin M.Keenerb
US National Poultry Research Center, USDA-ARS, Athens, GA 30605, United States of America
Response surface methodology (RSM) was used to optimize in-package cold plasma (IPCP) treatment for raw chicken breast meat. Non-inoculated and inoculated samples with Campylobacter (5.06 log10 CFU/mL) and Salmonella (5.40 log10 CFU/mL) were packaged in 35% O2/60% CO2, 65% O2/30% CO2, or 95% O2/0% CO2 and treated at 60, 70, or 80 kV for 60, 180, or 300 s. Microbial counts, color, pH, and drip loss were measured. There were no differences in Campylobacter, Salmonella, drip loss, or pH between treatments. IPCP could reduce psychrophiles by >1.0 log, depending on O2 and voltage interaction. Treatment effects on meat color varied by CIE L*a*b*. RSM analysis suggested that packaging atmosphere with 35% O2 and 60% CO2 and IPCP at 60 kV for 60 s were the optimal condition for maximizing microbiological shelf-life and minimizing appearance changes in raw chicken meat packaged in a barrier film and stored at 4 °C for 5 days.
The current study used response surface methodology to determine the optimal condition in the combination of voltage and time of an in-package cold plasma (IPCP) treatment and modified atmosphere (MA) packaging for extending shelf life and reducing food safety risk of pre-packaged raw chicken breast meat during refrigerated storage. Our data provided evidence that the optimal IPCP-treatment parameters and packaging atmosphere varied with targeted microorganisms and CIEL*a*b* color indicators. In MA packaging, changes in IPCP treatment voltage and time did not affect populations of Campylobacter and Salmonella, drip loss and pH; however, low IPCP treatment voltage (60 kV) for short exposure time (60 s) was as effective as the high voltage (80 kV) for longer treatment time (300 s) against psychrophiles and could reduce the changes in raw meat appearance (indicated with CIEL* measurements) due to IPCP treatment. Reducing O2 in packages from 95 to 35% resulted in better inhibition of psychrophilic growth on raw meat and changes in raw meat appearance or meat color lightness. It is recommended to use MA of 35% O2 and 60% CO2 and IPCP treatment at 60 kV for 60 s to extend microbiological shelf life, improve food safety, and retain quality of raw chicken breast meat packaged with a barrier film and stored at refrigerated temperature.
Keywords:Dielectric barrier discharge, Campylobacter jejuni, CIE L*a*b*Modified atmosphere package, Non-thermal treatment Salmonella Typhimurium