Modified atmosphere packaging of ground turkey thigh meat
The objectives of this study were to develop MAP conditions, using mixtures of oxygen (O₂) and carbon dioxide (CO₂), to prolong the shelf-life of ground turkey thigh meat. The effect of fat level and effectiveness of natural antioxidants were evaluated.
Product quality was determined semi-weekly by sensory, microbial, chemical, and instrumental analysis to evaluate rancidity, and sensory flavor changes. Thiobarbituric acid (TBA) tests were conducted to objectively measure changes in oxidative rancidity. Microbial analysis included psychrotrophic, lactic acid, and anaerobic bacteria enumerations, pH determinations were conducted to evaluate the effects of each treatment on the meat. Instrumentation color analysis CIE L* a* b* values were determined to measure color changes.
Test results indicate the pH changed significantly only in the air packaged samples. Psychrotrophic, lactic acid and anaerobic bacteria counts were significantly lower (P<0.05) in the 100% CO₂ packaged samples, than all other treatments and the control. Low TBA values, less than 4, were found with the 100% CO₂ samples. Sensory evaluation found the 80% O₂/20% CO₂ and 60% O₂/40% CO₂ packages were no longer acceptable at day 14, and air samples were unacceptable at day 18. The 100% CO₂ sample maintained acceptable over-all taste throughout the test period. Colorimeter values did show the 100% CO₂ atmosphere caused discoloration of the product during the first week. Fat level did not affect microorganism growth or shelf-life extension.
Rosemary oleoresin was effective as an antioxidant. TBA values of rosemary treated samples remained under 1.0 for the entire 28-day storage period.