Combined treatments of low dose irradiation with antimicrobials for inactivation of foodborne pathogens on fresh pork

Abstract

Decontamination of fresh meats without negatively impact on their sensory quality is a big challenge. In this study, the single or combined effect of antimicrobials (chitosan, carvacrol, tea polyphenols) and low dose gamma irradiation (≤2 kGy) against Salmonella Typhimurium and Staphylococcus aureus on fresh pork meat were assessed. The effects of these treatments on the color and lipid oxidization of pork meat were also evaluated. Irradiation at 1 kGy reduced 2.2 logs of S. Typhimurium and 1.6 logs of S. aureus, while the treatments of 1 kGy irradiation combined with chitosan (1%)-carvacrol (0.2%) or chitosan (1%)-tea polyphenols (0.5%) achieved 3.2 log reduction of S. Typhimurium and 5.1 log reductions of S. aureus. Irradiation at 2 kGy in combination with chitosan-carvacrol obtained over 5 log reductions of S. Typhimurium and S. aureus. There was no recovery/regrowth of S. Typhimurium or S. aureus in vacuum packaged meat samples throughout the 14 d storage period. There were no significant differences among all meat samples in color (L*, a*, b* values) after 7 d, while the combined treatments increased the lightness (L*) after 14 d of storage at 4 °C. The treated meat samples had lower content of malondialdehyde, indicating less lipid oxidation in pork meat during storage. This study demonstrates that the combined low dose irradiation with these antimicrobial surface treatments is promising for improving fresh pork safety and quality.