Stability of lamb loin stored under refrigeration and packed in different modified atmosphere packaging systems
The aim of the present study was to evaluate the effect of different modified atmosphere packaging (MAP) systems (vacuum, 75% O2 + 25% CO2 and 100% CO2) on the stability of lamb loins stored at 1 ± 1 °C for 28 days. Microbiological (counts of aerobic and anaerobic psychrotrophic microorganisms, coliform at 45 °C, coagulase-positive staphylococci and lactic acid bacteria and presence of Salmonella), physical and chemical (thiobarbituric acid reactive substances [TBARS], objective color, pH, water loss from cooking [WLC] and shear force), sensory (acceptance testing using a 9-point hedonic scale) and gas composition analyses were performed. Lamb meat remained stable with respect to the majority of the evaluated physical and chemical indexes and within the standards established by Brazilian legislation for pathogenic microorganisms throughout the storage period in all three packaging systems. However, with respect to psychrotrophic microorganisms, 100% CO2 packaging system provided increased stability despite presenting lower appearance preference.
Conclusions
According to the results of the microbiological, physical and chemical evaluations, as well as the sensory acceptance of cooked meat, we conclude that the samples stored in packages containing 100% CO2 for 28 days at 1 °C have greater stability and better shelf life than vacuum-packed samples and those packaged in a 75% O2 + 25% CO2 atmosphere for 21 days. However, the 100% CO2 treatment was the least preferred in terms of the appearance of the raw meat while still packed when compared to the other MAP systems under evaluation. Therefore, despite presenting greater stability, further studies should be performed on the packaging of lamb meat at high concentrations of CO2. Other gases in combination with CO2 may enable the maintenance of a more acceptable color of the packaged meat, especially when it is intended for retail sales.