George M H, Tatum J D, Belk K E, Smith G C
Department of Animal Sciences, Colorado State University, Fort Collins 80523, USA.
J Anim Sci. 1999 Jul;77(7):1735-41. doi: 10.2527/1999.7771735x.
An audit of supermarkets in eight U.S. cities was conducted to characterize retail beef loin steaks with respect to grade, postfabrication aging, and tenderness and to provide an interim measure of progress in industry efforts to improve retail beef tenderness. Top sirloin steaks (n = 819) and strip loin steaks (n = 827 paired steaks) were purchased at retail markets in Atlanta, Chicago, Denver, Houston, Philadelphia, Phoenix, San Francisco, and Seattle and shipped to Colorado State University for measurement of shear force (both cut types) and evaluation by a trained sensory panel (strip loins only). Approximately 80% of the steaks originated from beef plants in Kansas, Texas, Nebraska, and Colorado. Postfabrication aging periods ranged from 2 to 87 d (mean = 20.8 d) for top sirloin steaks and from 2 to 91 d (mean = 19.2 d) for strip loin steaks, although most top sirloin (85%) and strip loin (91%) steaks were available for purchase 7 to 35 d after fabrication. The mix of quality grades was similar for both cuts: 60% Select, 31% "commodity" Choice, 6 to 7% "Certified" Choice, and 2 to 3% Prime. Shear force averaged 3.46 kg (SD = .74) for top sirloins and 3.05 kg (SD = .95) for strip loins; 75% of both steak types had shear force values between 2 and 4 kg. Postfabrication periods shorter than 7 d were associated with reduced (P < .05) tenderness, especially for top sirloin steaks. Higher quality grades were associated with greater (P < .05) tenderness (Prime > Choice > Select) for both cuts. Based on panel tenderness ratings, the approximate odds of obtaining a "slightly tough" or tougher strip loin steak at a retail supermarket were: 0 for Prime, 1 in 10 for "Certified" Choice, 1 in 5 for "commodity" Choice, and 1 in 4 for Select. Audit results suggest that tenderness characteristics of loin steaks have not changed materially since the National Beef Tenderness Survey was conducted in 1991 and that two primary focal points of the beef industry's efforts to improve tenderness should be 1) to prevent short-aged (< 7 d postfabrication) product from reaching consumers and 2) to identify methods for enhancing tenderness of Select and "commodity" Choice beef.
对美国八个城市的超市进行了一项审计,以描述零售腰大肌牛排的等级、加工后熟化情况和嫩度,并为牛肉行业改善零售牛肉嫩度的努力提供一个中期进展衡量指标。上腰部牛排(n = 819)和里脊牛排(n = 827对)在亚特兰大、芝加哥、丹佛、休斯顿、费城、凤凰城、旧金山和西雅图的零售市场购买,然后运往科罗拉多州立大学测量剪切力(两种切块类型),并由经过培训的感官小组进行评估(仅里脊牛排)。大约80%的牛排来自堪萨斯州、得克萨斯州、内布拉斯加州和科罗拉多州的牛肉加工厂。上腰部牛排加工后的熟化期为2至87天(平均 = 20.8天),里脊牛排为2至91天(平均 = 19.2天),不过大多数上腰部牛排(85%)和里脊牛排(91%)在加工后7至35天即可购买。两种切块的质量等级组合相似:60%为精选级,31%为“普通”特选级,6%至7%为“认证”特选级,2%至3%为顶级。上腰部牛排的剪切力平均为3.46千克(标准差 = 0.74),里脊牛排为3.05千克(标准差 = 0.95);两种牛排类型中75%的剪切力值在2至4千克之间。加工后熟化期短于7天与嫩度降低(P < 0.05)有关,尤其是上腰部牛排。对于两种切块,较高的质量等级与更高的嫩度(P < 0.05)相关(顶级 > 特选级 > 精选级)。根据小组的嫩度评级,在零售超市买到“略硬”或更硬的里脊牛排的大致概率为:顶级为0,“认证”特选级为十分之一,“普通”特选级为五分之一,精选级为四分之一。审计结果表明,自1991年进行全国牛肉嫩度调查以来,腰大肌牛排的嫩度特征没有实质性变化,牛肉行业改善嫩度的两个主要重点应该是:1)防止短时间熟化(加工后 < 7天)的产品流向消费者;2)确定提高精选级和“普通”特选级牛肉嫩度的方法。