Evaluating the impact of differing surface areas and weights of beef strip loin and sirloin steaks in tri-gas modified atmosphere master bags on retail display

The objective of this study was to evaluate the impact of differing surface areas and weights of steaks in CO-MAP on shelf stability and to establish standards for optimal surface area and weight of meat for oxygen scavenger capacity. Thirty-two beef strip loins (IMPS #180) and forty-eight top sirloin butts (IMPS #184) both USDA Low-Choice were obtained from a commercial processor and wet aged to 21 d postmortem. Strip loins and top butts were alternately cut based on the different thicknesses required to obtain steaks for weight treatments and surface area treatments. Strip steak weight treatments were light weight (LW), intermediate weight (IW), and heavy weight (HW) and surface areas were small surface area (SS), medium surface area (MS), and large surface area (LS). Sirloin steak weight treatments were the same as strips and surface areas were small surface area (SS) and large surface area (LS). After slicing, steaks were placed into foam trays (n = 50 strip steaks; n = 46 sirloin steaks) with an absorbent pad and overwrapped with perforated polyvinyl chloride film. Trays were placed in master bags and flushed with 30% CO2, 0.4% CO, and 69.6% N2 before dark storage of 15 d. Oxygen depletion and headspace analysis were conducted, and objective and subjective color measurements were collected during retail display (d 1 – 7 strips; d 1 – 6 sirloins). Lipid oxidation, oxygen consumption, and metmyoglobin reducing ability were obtained at the beginning and end of retail display. Muscle color, surface discoloration, and overall acceptability were analyzed by a trained panel (n = 6). Treatments of surface area and weight performed comparable to each other for both strip and sirloin steaks. In this study, no effect of surface area or weight in a CO-MAP master bag was observed. Therefore, it is believed that the scavenger utilized in this study had sufficient capacity to overcome the additional weight or surface area in the master bag.