Impact of Aging Methods and Frozen Storage on Beef Quality Attributes from Different Finishing Diets

Abstract

The effects of finishing diet (pasture or grain) and meat preservation method on beef’s physicochemical, micro- biological, and sensory attributes were evaluated. The preservation methods assessed were dry aging in bag (DAb) and wet aging (WA) for 40 d, and then frozen storage (Fr) ([DAb + Fr] and [WA + Fr]) for 180 d. Sixty striploins (Longissimus lumborum) from British breed steers (n = 15 from pasture and n = 15 from grain-based diet) were used. Lightness (L*) was only affected by finishing diet where meat from grain-fed steers was lighter than those fed on pasture (P < 0.01). DAb meat had higher pH (P < 0.01) and lower cooking losses (P < 0.01) than WA. DAb + Fr had the highest Psychotrophic bacteria counts compared to WA + Fr, DAb and WA (P < 0.01). DAb and DAb + Fr increased Enterobacteriaceae bacteria counts (P < 0.01) compared to WA and WA + Fr. DAb + Fr samples had the lowest L*, a*, and b* values. No interaction between physicochemical characteristics (color coordinates, pH, cooking losses, and shear force) and surface microbiological load was observed (P > 0.05). Greater polyunsaturated fatty acids (PUFA), PUFA n-3, conjugated linoleic acid (c9, t11 – 18:2) (P < 0.01), and PUFA/saturated fatty acid ratio (P < 0.05) and lower n-6:n-3 ratio (P < 0.01) were observed in pasture- than grain-fed steers. The consumer sensory panel showed acceptable scores for all treatments, although some differences between attributes were detected by cluster analysis. Different aging methods followed by a frozen storage period could be used to produce and export meat with the required quality attributes to meet consumer expectations