Luzardo, Santiago, authorBelk, Keith E., advisorWoerner, Dale R., committee memberTatum, J. Daryl, committee memberHess, Ann M., committee member2016-07-122016-07-122016http://hdl.handle.net/10217/173338The objective of this study was to evaluate the influence of packaging during storage of strip loins (to simulate export shipment) from steers fattened on intensive grazing systems (Uruguay; UR) or on high concentrate diet (United States; US) on retail display life color, microbial growth, fatty acids profile, lipid peroxidation and vitamin E content. Four different packaging treatments were applied to UR and US strip loins or steaks during 35 d storage; treatments were applied 7 d following slaughter. After 35 d storage, the samples were evaluated during simulated retail display for 6 d. In block 1, the treatments were: vacuum packaging (VP); low-oxygen modified atmosphere packaging (MAP) with nitrogen (N2) and CO2 (MAP/CO2); low oxygen MAP with N2 plus CO2 and carbon monoxide (CO); VP plus an application of peroxyacetic acid (VP/PAA). In block 2, the treatments were: VP, MAP/CO and VP with ethyl-N-lauroyl-L arginate HCl (LAE) incorporated into the film as an antimicrobial agent (VP/AM). In block 3, the treatments were: VP, MAP/CO2, MAP/CO and VP/AM. Regardless of production system and packaging treatment, mesophilic and psychrotrophic counts of 6.9 to 7.8 log10 CFU/cm2, and 6.7 to 7.7 log10 CFU/cm2, respectively, were obtained at the end of retail display, except for US samples in blocks 2 and 3 (5.5 to 6.3 log10 CFU/cm2). The UR strip loins packaged with MAP/CO had greater (P < 0.05) a* values than product packaged in VP/PA and MAP/CO2 following 6 d of display. For US beef, the MAP/CO treatment resulted in the reddest lean color (P < 0.05) compared to the other three packaging treatments in block 1. In blocks 2 and 3, the UR strip loin steaks packaged in MAP/CO also had the greatest a* values compared to the other three treatments, but no differences (P > 0.05) were detected among the VP treatments and the MAP/CO in the US steaks at the end of retail display. Only system (in block 1, and blocks 2 and 3), and time (in block 1) affected (P < 0.005) lightness (L*). In all blocks, US samples had greater L* values than UR samples (32.6 vs. 28.5; P = 0.0015, for block 1; and 33.4 vs. 31.1; P < 0.0001 for blocks 2 and 3). Vitamin E content in UR steaks, regardless of packaging treatment, was greater (P < 0.05) than US steaks. No effect of packaging treatment (P > 0.05) was observed by country of origin at the different display times in block 1, but UR beef displayed for 0 d from the MAP/CO2 treatment had greater (P < 0.05) vitamin E content than beef from the other three packaging treatments in blocks 2 and 3. Packaging x system, system x time and packaging x system x time interactions were not significant for any of the fatty acids analyzed on this study. Beef from UR had lower (P < 0.05) SFA and MUFA concentrations and greater (P < 0.05) PUFA, n-6 and n-3 concentrations than US beef when evaluated during retail display. Beef from UR developed more detectable (P < 0.05) oxidized odor than US samples while the latter exhibited a greater (P < 0.05) sour odor than UR grass-fed samples. Values from TBARS were influenced by significant packaging x system x time interaction in block 1 (P = 0.0027) and in blocks 2 and 3 (P = 0.0104). In block 1, UR beef had a greater (P < 0.001) TBARS values than US samples on d 0 of display, but TBARS values tended to decrease during retail display and differences almost disappear by the end of the display period. For blocks 2 and 3, TBARS value tended to increase between d 0 to d 6 of retail display in the UR and US samples. Complexity of fresh meat post-mortem chemistry warrants a more comprehensive and systemic approach to maximize shelf-life.born digitaldoctoral dissertationsengCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.microbial growthproduction systemstrip loinpackagingbeefshelf-lifeText