The effect of wet ageing duration (up to 14 weeks) on the quality and shelf-life of grass and grain-fed beef

Abstract

The quality, colour, and shelf-life of wet aged grass and grain-fed beef were compared. Striploins (n = 24) were each divided into 6 portions and were assigned to different ageing periods (0, 3, 5, 8, 11, or 14 weeks). Analysis demonstrated that declines in shear force and particle size occurred within the first 3 weeks of ageing. Extended ageing resulted in increases in beef purge and pH; and decreases in total moisture, drip, and cooking loss. The initial grass-fed beef drip (3.1%) and particle sizes (201.0 μm) were higher than for grain-fed beef (1.8% and 145.2 μm, respectively). Total viable counts were > 7 cfu/g after 5 weeks of ageing. Total volatile basic nitrogen was < 15 mg/100 g, even after 14 weeks of ageing. Product line by ageing period interactions affected vitamin E and colour parameters. In conclusion, wet aged beef maintains 'acceptable' microbial loads for 5-8 weeks, irrespective of product line and without any deterioration in its quality.

Keywords: Beef; Feeding system; Retail colour; Shear force; Total volatile basic nitrogen (TVB-N); Wet ageing.