Effect of packaging during storage time on retail display shelf life of longissimus muscle from two different beef production systems

Two studies were conducted to evaluate the influence of packaging and production system (PS) on retail display life color (L*, a*, and b*), fatty acid profile (% of total fatty acids), lipid oxidation (thiobarbituric acid reactive substances; mg malondialdehyde/ kg of muscle), vitamin E content (μg/g of muscle), and odor (trained panelists) during storage of LM. Four (or 3) different packaging treatments were applied to LM from steers fattened on grazing systems (Uruguayan) or on high-concentrate diets (U.S.). From fabrication to application of treatments, Uruguayan LM were vacuum packaged for air shipment and U.S. LM were also vacuum packaged and kept in a cooler until Uruguayan samples arrived. Treatments were applied 7 d after slaughter. In Exp. 1, treatments were vacuum packaging (VP), lowoxygen (O₂) modified atmosphere packaging (MAP) with nitrogen (N2) and carbon dioxide (MAP/CO₂), low-O₂ MAP with N2 plus CO₂ and carbon monoxide (MAP/CO), and VP plus an application of peroxyacetic acid (VP/PAA). In Exp. 2 block 1, treatments were VP, MAP/CO, and VP with ethyl-N-lauroyl-l-arginate HCl incorporated into the film as an antimicrobial agent (VP/ AM). In Exp. 2 block 2, treatments were VP, MAP/CO₂, MAP/CO, and VP/AM. After 35 d storage, steaks were evaluated during simulated retail display for up to 6 d. In Exp. 1, Uruguayan steaks under MAP/CO had greater (P < 0.05) a* values than VP/PAA and MAP/CO₂ on d 6 of display. For U.S. beef, the MAP/CO had the reddest lean color (P < 0.05) compared with the other 3 packaging treatments on d 6 of display in Exp. 1. Packaging × PS × time interaction was significant (P < 0.05) in Exp. 1. In Exp. 2, MAP/CO in Uruguayan steaks also had the greatest a* values on d 6 of display, but no differences (P > 0.05) were detected among both VP and MAP/CO in U.S. steaks at this time. No significant (P > 0.05) packaging × PS × time interaction was observed in Exp. 2. Only PS (both experiments) and time (Exp. 1) affected (P < 0.05) L* values. In both experiments, U.S. steaks had greater (P < 0.05) L* values than Uruguayan steaks. Vitamin E content in Uruguayan steaks was greater (P < 0.05) than in U.S. steaks. Packaging × PS, PS × time, and packaging × PS × time interactions were not significant (P > 0.05) for any of the fatty acids. Beef from Uruguayan had lower (P < 0.05) SFA and MUFA and greater (P < 0.05) PUFA and n-6 and n-3 fatty acid percentages than U.S. beef. Complexity of fresh meat postmortem chemistry warrants a more comprehensive approach to maximize shelf life.