Maria Lundesjö Ahnström

Dry aging of beef in a bag highly permeable to water vapour.

The objective of this experiment was to compare traditional dry aging of beef with a novel technique of dry aging in a highly moisture-permeable bag. Four equal-sized sections from paired beef strip loins were dry aged traditionally, unpackaged, or packaged in the experimental bag for 14 or 21d at 3°C. No differences (P>0.05) were noted for pH, moisture, fat, total plate counts, cook loss, shear force, or any measured sensory attribute between the two aging treatments after either aging period. After 21d, however, dry aging in the bag (versus traditional dry aging) decreased (P<0.05) weight loss during aging, trim loss after aging, and yeast counts on lean tissue and increased lactic acid bacteria counts (P<0.05) on adipose and lean tissue. Dry aging in a highly moisture-permeable bag is feasible, will positively impact yields and reduce microbial spoilage, and will have no negative impact on product quality.

Vacuum skin pack of beef — A consumer friendly alternative

The aim of this study was to assess how beef quality traits are affected by skin packaging compared with vacuum and high-oxygen modified atmosphere packaging (MAP; 80% O(2) and 20% CO(2)). Both M. longissimus dorsi from 6 young bulls were cut and aged in vacuum for 7 days and then cut into 3.5-cm steaks, thereafter either frozen directly day 7 or stored in skin pack, vacuum pack or MAP for an additional 7 or 14 days and then frozen. Warner-Bratzler shear force, loss and colour were measured and sensory analysis was performed. The results showed no differences in shear force, sensory analysis and total loss between steaks packed in skin pack or vacuum, but skin packed steaks had lower purge loss. MAP steaks had lower sensory scores than the other treatments at days 14 and 21. Raw MAP-steaks were bright red, but showed signs of premature browning when cooked.

Pelvic suspension improves quality characteristics in M. semimembranosus from Swedish dual purpose young bulls

To study whether pelvic suspension would improve tenderness in comparison with normal hanging from the achilles tendon, carcasses from 34 Swedish red and white young bulls were randomly selected at the slaughter line. The left sides of the carcasses were re-hanged by the pelvic bone before cooling whereas the right sides remained hanging from the achilles tendon. Quality characteristics and length and weight were studied for M. semimembranosus. Tenderness was measured by the Warner-Bratzler shear force method. Purge and cooking loss were determined and sarcomere length was measured. Pelvic suspension considerably affected the shape of M. semimembranosus; the length increased by 38% in comparison with achilles suspension. The elongation of the muscle was parallel with an increase in sarcomere length from 1.6 to 2.9μm. The water-holding capacity was improved because both purge and cooking loss were lower for pelvic suspended carcasses. Tenderness was improved and the coefficient of variation between animals for Warner-Bratzler shear force was reduced from 26% for achilles tendon suspension to 12% for pelvic suspension. Likewise, the within-animal variation for shear force decreased significantly from 13.3% to 10.0%. Therefore, pelvic suspension seems to be a reliable method to reduce texture variability in M. semimembranosus from young bulls.

Effects of pelvic suspension of beef carcasses on quality and physical traits of five muscles from four gender-age groups.

Pelvic and Achilles suspension methods for beef carcasses were compared for four gender-age groups (24month bulls, 34month bulls, heifers, and cows) and five muscles [M. longissimus dorsi (LD), M. semimembranosus (SM), M. adductor (AD), M. psoas major (PM), and M. gluteus medius (GM)]. Pelvic suspension increased muscle and sarcomere lengths in the SM, LD, GM, and AD muscles. The following effects were significant (p<0.05). Peak force was reduced by pelvic suspension in the LD and GM of bulls-24 and bulls-34, but not heifers and cows. Furthermore, peak forces decreased for the SM after pelvic suspension in bulls-24, bulls-34, and heifers. For the AD, the only decrease in peak force was for bulls-34. Water-holding capacity increased and purge in vacuum bags decreased for pelvic suspension of all muscles except the PM. Although the effects of pelvic suspension varied somewhat between gender-age groups and muscles, this method of hanging carcasses merits industrial consideration because it improves muscle yields, tenderness, and reduces variation within muscles.

Influence of carcass suspension on meat quality of Charolais heifers from two sustainable feeding regimes.

This study investigated the effects of pelvic suspension on the meat quality of M. longissimus dorsi, M. semimembranosus and M. adductor from 35 heifers with at least 75% Charolais breeding. Two-thirds of the heifers were slaughtered directly from pasture at 18 months of age and one-third was finished indoors and slaughtered at 22 months. After slaughter and electrical stimulation one side of each carcass was re-suspended by either the achilles tendon or the pelvic bone. Longissimus muscles were aged 7 or 14 days and were then evaluated for drip loss, colour, shear force and sensory analysis. As compared to 18-month-old heifers, 22-month-old heifers were heavier, more muscular and fatter (P < 0.05). Intramuscular fat content increased with slaughter age (P < 0.003). Pelvic suspension reduced longissimus peak force values, total energy, pH and thawing losses (P < 0.05) in heifers slaughtered at 18 months. Semimembranosus showed the largest response to pelvic suspension with significantly lower peak force and total energy values. Finishing for 4 months did not affect longissimus shear forces. Achilles-suspended samples had lower shear force values after 14 v. 7 days of ageing. Pelvic-suspended samples aged 7 days were, however, just as tender as those aged 14 days. Sensory analysis of longissimus samples aged 14 days showed that samples from pelvic-suspended sides had higher tenderness, lower bite resistance, more meaty taste and less visible marbling compared with samples from achilles-suspended carcasses.

A novel method to dry age beef by using vacuum packaging

The traditional dry-aging method for beef was compared with a novel technique of dry aging in a highly moisture-permeable vacuum bag. Paired beef strip loins were cut into four sections and were dry aged traditionally (unpackaged) or packaged in the novel bag for 14 or 21 days. Cooking loss, tenderness, juiciness, and all flavor attributes were similar for the aging methods. Beef dry aged in the bag had less weight loss during aging, less trim loss after 21 days, and lower yeast counts after either aging time, compared with beef dry aged unpackaged. This novel method of dry aging beef in a vacuum bag can increase yields, decrease microbial contamination, and provide processors greater flexibility of facility use, all of which would positively impact processors’ profits.