Phosphate buffer saline (pbs)

Standard plate count technique was used to determine the initial microbial concentration and the efficiency of the treatment in reducing the number of microorganisms on the surface of the sample. After each treatment, chicken meat samples were collected in sterile Falcon tubes, mixed with 9 mL of Phosphate Buffer Saline (PBS; 0.01 M, pH 7.4; Oxoid, UK), and homogenized at 35 Hz for 1 min (Stomacher 400; International P.B.I., Milan, Italy). The solution was serially diluted (1:10) in PBS; 100 µ L of the solution was plated in duplicate onto the selective media Chromatic Coli/Coliform Agar (Liofilchem, Italia) for E. coli, and on Rose Bengal (RB) (Microbiol, Cagliari, IT) for yeasts and molds, while 1 mL was pour-plated into Plate Count Agar (PCA, Sacco, Como, IT) for the determination of the total mesophilic count. The incubation temperature and time were 37°C and 24 h for E. coli, and 30 and 22°C for 3 to 5 D for PCA and RB plates, respectively. The inactivation degree was determined by evaluating the log(N/N₀), where N₀(CFU/g) is the number of colony forming units per mL initially present in the untreated sample, and N (CFU/g) is the number of survivors after the treatment. At least 3 independent experiments were carried out for each single treatment condition, and the results were expressed as mean and standard deviation. Each experiment was performed at least in triplicate.