Carcass composition of "bob" and "special-fed" veal and its prediction.

Percentage of lean, fat, and bone were determined in 18 bob veal (BV) and 28 special-fed veal (SFV) carcasses. Carcasses were subjected to a set of visual conformation scores and a variety of physical measurements. No significant differences were found regarding carcass percentage of lean, fat, and bone within the three BV weight groups (P > .05). On average, SFV were 12% fatter than BV and did not have a greater percentage of lean (P > .05), except for SFV carcasses weighing 88.2 to 97.7 kg. Bob veal had less fat (internal, external, and intermuscular) and a higher bone percentage than SFV (P < .05). The round and shoulder primals had the greatest proportion of lean in both the BV and SFV carcasses. Bob veal carcasses had an average conformation score of average Good and SFV carcasses had an average conformation score of average Choice. In addition, a parsimonious subset of variables was identified for predicting total percentage of lean (TPLEAN) for both BV and SFV separately, using "stepwise" regression model building procedures. For BV, all four identified predictor variables were subjective conformation scores (i.e., muscling, appearance, leg thickness, loin-back plumpness) (R = .73, P < .03). For SFV, four predictor variables were also identified: kidney and pelvic fat, fat thickness, carcass length, and lateral thickness (R = .61, P < .03). Although both regression equations were significant predictors of TPLEAN, confidence limits for predicting future TPLEAN value were wide relative to the variation in the actual TPLEAN values. Thus, the practical utility of the regression equations is limited.

Pigment oxidation in ground veal: Influence of lipid oxidation, iron and zinc.

The color stability of fresh ground veal from four different muscles (biceps femoris, longissimus dorsi, psoas major and supraspinatus) was characterized, and the effects of lipid oxidation, iron and zinc on this degradative process were investigated. Samples were minced and prepared in a manner consistent with retail production and analyzed for pH, myoglobin concentration, total and nonheme iron, and zinc. Pigment and lipid oxidation were measured on days 0, 3 and 6 of 4°C storage. B. femoris demonstrated the greatest extent of lipid oxidation, and was more color-labile than p. major or supraspinatus (P < 0·05), but no different from l. dorsi (P > 0·05). Total iron and myoglobin concentrations were lowest for l. dorsi (P<0·05). Zinc concentration in the four muscles followed the order supraspinatus ⩾ b. femoris ⩾ l. dorsi ⩾ p. major (P < 0·05). Data analysis revealed that initial metmyoglobin formation (days 0 to 3) was significantly correlated with total iron (r = 0·69) or nonheme iron (r = 0·68) in b. femoris, but not any of the other muscles. Correlations between lipid and pigment oxidation in each of the four muscles were performed and the data support a strong relationship between these degradative processes in ground veal.

Ineffectiveness of Three Added Mold Species to Enhance the Rapid Aging of Beef.

Paired beef short loin sections from four U.S. Good and four U.S. Choice carcasses were used to determine the effects of the mold Thamnidium elegans on cooking and palatability characteristics. The longissimus muscle from each section was treated with mold spores and aged for 2 or 4 d or left untreated and aged for 2 or 14 d at 4°C. Sensory panel ratings revealed that mold treatment had no significant effect (P<0.05) on tenderness, juiciness, detectable connective tissue amount, or beef flavor intensity of the loins aged for 2 d. Thawing loss, cooking loss, cooking time, Instron shear force and work force values were not affected (P>0.05) by treatment with T. elegans . Aging untreated meat for 14 d significantly improved (P<0.05) sensory panel ratings for tenderness. No significant difference (P>0.05) was noted between mold treatments (2 and 4 d) when compared to the 14-d untreated aging, for beef flavor intensity, detectable connective tissue amount, shear and work force values. Significant grade effects were noted with U.S. Choice samples having higher (P<0.05) sensory panel ratings for juiciness and beef flavor intensity, and decreased (P<0.05) ratings for connective tissue amount when compared with U.S. Good samples. The data indicate that treatment of sub-primal cuts with T. elegans has little or no effect on palatability and cooking characteristics.

Dietary fat and cancer: a perspective from the livestock and meat industry.

It has been a popular belief that U.S. consumers ingest approximately 40% of their calories as fat and that a high percentage is from animal sources. In fact, animal fat consumption has declined 23% in the past 20 years and the increase in fat consumption has been solely due to vegetable (plant) sources. The decline in animal fat production probably explains why the estimates discussed in this presentation fall below earlier literature references. The validity of the estimates presented here will be determined as part of an in depth study undertaken by the National Academy of Sciences' Board of Agriculture. If this comprehensive study substantiates the values presented in this paper and other recent publications, a reconsideration of the impact of animal source fats on caloric intake and diet related diseases is indicated. The U.S. livestock and meat industry is extremely aware of and responsive to the role of meat and meat products in the nutrition, health and well-being of the nation. Research programs are designed with these factors as a guide and producers continue to adjust product characteristics to meet the changing needs.

Antibacterial Nature of Molds Isolated from Aged Beef.

The antibacterial and competitive nature of the molds Thamnidium elegans , Mucor mucedo and Chaetostylum fresenii , commonly isolated from beef aging at refrigeration temperature for extended periods, were examined to determine if their presence on meat would inhibit bacterial growth. An agar plate method revealed no growth inhibition of six strains of meat spoilage bacteria by the molds examined. Eye round (semitendinosus) roasts were inoculated with spore suspensions containing nine strains of the three fungal species and incubated for 48 h at 4 or 18°C. Initial aerobic bacterial counts (35°C) on the meat samples were 2.4 × 104 CFU/cm2. Mold treatment had no significant effect (P>0.05) on reduction of aerobic bacterial counts (35 and 7°C), coliforms or fecal streptococci when compared with uninoculated controls. No surface fungal growth was evident after 48 h at 4°C, the normal storage temperature for meat, whereas appreciable mycelial development was apparent after 48 h at 18°C. T. elegans , M. mucedo and C. fresenii were not capable of reducing or controlling bacterial growth on meat surfaces at refrigeration or elevated temperatures.

Proteolytic and Lipolytic Activity of Molds Isolated from Aged Beef.

This study evaluated the proteolytic and lipolytic activity of several strains of Thamnidium elegans , Mucor mucedo and Chaetostylum fresenii on selected test proteins and lipids. At 18°C, the zone of hydrolysis to colony size ratio on skim milk agar, representing proteolytic activity after 4 d, was 0.92, 0.80 and 0.67 for M. mucedo , C. fresenii and T. elegans , respectively. A similar trend was noted after 4 d of incubation at 24°C. There was positive lipolytic activity on Tween 80 at 18 and 24°C for the same three molds. The proteolytic and lipolytic activity decreased with decreasing temperatures so that at 4°C, the temperature of most probable use if applied to meat, the effect was negligible unless long incubation times were used. The absence of proteolytic activity of the molds at 4°C and the impracticality of aging beef at 18 or 24°C suggest that treatment of meat with molds to enhance tenderness may not be feasible.