Chitosan dipping or oregano oil treatments, singly or combined on modified atmosphere packaged chicken breast meat

The present study examined the effect of natural antimicrobials: chitosan, oregano and their combination, on the shelf-life of modified atmosphere packaged chicken breast meat stored at 4 °C. Treatments examined in the present study were the following: M (control samples stored under modified atmosphere packaging), M–O (samples treated with oregano oil 0.25% v/w, stored under MAP), M–CH (samples treated with chitosan 1.5% w/v, stored under MAP) and M–CH–O (treated with chitosan 1.5% w/v and oregano oil 0.25% v/w, stored under MAP). Treatment, M–CH–O, significantly affected mesophilic Total Plate Counts (TPC), lactic acid bacteria (LAB), Brochothrix thermosphacta, Enterobacteriaceae, Pseudomonas spp., and yeasts-moulds during the storage period. Lipid oxidation (as determined by MDA values) of control and treated chicken samples was in general low and below 0.5 mg MDA/kg, showing no oxidative rancidity during the storage period. Addition of chitosan to the chicken samples produced higher (P < 0.05) lightness (L*) values as compared to the control samples. The results of this study indicate that the shelf-life of chicken fillets can be extended using, either oregano oil singly, and/or chitosan, by approximately 6 (M–O) and > 15 (M–CH and M–CH–O) days. Interestingly, chitosan (M–CH) or chitosan–oregano (M–CH–O) treated chicken samples were sensorially acceptable during the entire refrigerated storage period of 21 days. It is noteworthy that the presence of chitosan in M–CH and M–CH–O samples did not negatively influence the taste of chicken samples, with M–CH samples receiving a higher score (compared to M–CH–O), probably as a result of a distinct and “spicy” lemon taste of chitosan, that was well received by the panelists. Based primarily on sensory data (taste attribute) M–CH and M–O treatments extended the shelf-life of chicken fillets by 6 days, while M–CH–O treatment resulted in a product with a shelf-life of 14 days, maintaining acceptable sensory characteristics.