Confinement odour, quality, and safety of thawed lamb racks, frozen after an initial ageing period of up to 3 weeks

Abstract

French trimmed lamb racks (longissimus lumborum muscle, LL) were vacuum packaged, wet aged for 0, 1, 2, or 3 weeks (6 per ageing period, n = 24), and frozen. Thawed lamb racks were scored by consumers for pre-opening pack assessment, post-opening pack assessment and post-blooming sample assessment. Objective quality assessments for freshness and quality were then applied to these lamb racks. The sliminess and overall odour were higher after 3 weeks of ageing prior to freezing compared with 0 weeks ageing (P < 0.01). In addition, the total viable microbial counts (TVC) and ultimate pH were also higher after 3 weeks of ageing (P < 0.05); however, all values were within acceptable levels. The overall liking and freshness appearance during the post-opening pack assessment was inconsistent with ageing period (P < 0.05); although, there was no difference between ageing for 1 or 3 weeks prior to freezing, indicating there is no apparent advantage to ageing lamb racks for longer than 1 week prior to freezing. Furthermore, total viable basic nitrogen (TVB-N), total myoglobin and all the colour parameters did not differ (P > 0.05) and were within acceptable limits defined for fresh meat. Cooking loss, drip loss, expressible moisture and thaw loss were also unaffected by ageing period (P > 0.05). Overall, the results of this study indicate there is no benefit of ageing bone-in lamb racks for periods longer than 1 week prior to freezing, in terms of consumers’ satisfaction.