Characterization of beef semimembranosus and adductor muscles from US and Mexican origin

Mexican consumers at the point of meat purchase. Beef choice

Within-consumer preference replication achieved through systematic image manipulation was used in consumer surveys in four cities across Mexico (Mexico City, n=195; Guadalajara, n=100; Hermosillo, n=132; Veracruz, n=61) to study beef preferences. Images of beef steaks controlled for lean and fat colour, fat cover and marbling were presented to consumers to determine the characteristics used in beef choice and the levels of preference of these characteristics. The most important choice criteria were fat cover (62% preferring little fat cover) and marbling (59% preferring non-marbled). Lean colour was also important with 24% and 29% choosing light and dark red beef, respectively. Fat colour was the least important of the four attributes studied (18% and 19% choosing white and yellow, respectively), but was nevertheless important given that 43% of consumers used three or four characteristics to make their choice. Imported and domestic beef in the Mexican marketplace appear to respond to the range of consumers' beef preferences at the point of purchase.

Effect of an allostatic modulator on stress blood indicators and meat quality of commercial young bulls in Mexico

To assess the effect of an allostatic modulator (AM) on stress blood indicators and meat quality traits, the feed of 80 non-castrated 18-20 month-old bulls was supplemented with 10 g/day of an AM for 30 days before slaughter. Another 80 bulls served as control animals. The AM was comprised of ascorbic acid, acetoxybenzoic acid and sodium and potassium chloride. Blood samples were taken at slaughter for analyses of hematocrit value, erythrocyte and leukocyte counts, and glucose, lactate and cortisol concentrations. Post-mortem measures of meat color and pH were made at 24h and color, shear force and cooking loss on meat from 20 animals at 28 days. The AM supplementation resulted in lower hematocrit value, erythrocyte count and glucose level (P<0.05), higher a* (P<0.0001) and b* (P<0.0001) at 24h and lower b* (P<0.05) at 28 days. Thus AM treatment improved some stress blood indicators and meat color and therefore merits further investigation.

Study of the Warner-Bratzler shear force, sensory analysis and sarcomere length as indicators of the tenderness of sun-dried beef

Sun-dried beef is a frequently consumed and valued product in Brazil, however, there have been no scientific studies on its texture. To assess the tenderness of sun-dried beef, an instrumental analysis (Warner-Bratzler Shear Force; WBSF), a sensory analysis (Quantitative Descriptive Analysis; QDA) and the sarcomere length (SL) were used as indicators. Significant differences were observed among the sun-dried beef samples. Sample 3 (composed of sun-dried meat purchased at three fairs from Region 3 in the city of João Pessoa-PB) was considered the most tender by the assessors, with a score of 6.7, and its WBSF analysis revealed a maximum value of 2.70 kgf. Additionally, this sample exhibited the highest SL value (1.89 µm). Samples 1 and 2 (composed of sun-dried meat purchased at three fairs from Regions 1 and 2, respectively, in the city of João Pessoa) exhibited very similar tenderness values (WBSF and QDA) but differed in their SL values, which suggested that sample 2 was the least tender. In conclusion, these results demonstrate that the studied parameters are complementary and can be used as tenderness indicators for sun-dried beef. However, although the difference was beyond the detection limit of the assessors and the texturometer, the SL analysis appears to have been the most effective.

Chemical composition and cooking properties of beef forequarter muscles of Mexican cattle from different genotypes

Beef forequarter muscles biceps brachii (BRB), brachialis (BRA), complexus (COM), splenius (SPL), infraspinatus (INF), teres major (TER), rhomboideus (RHO), subscapularis (SUB), supraspinatus (SUP), triceps brachii long-head (TRB) and triceps brachii lateral-head (TRI) were obtained from Mexican beef carcasses originated from Bos indicus (Bi, n=10) or Bos taurus (Bt, n=10) young bulls. Muscles were analyzed for WBSF, cooking loss, and moisture and fat contents. INF had the lowest WBSF (37.23N) and cooking loss (31.78%) of all. RHO exhibited the lowest moisture (72.62%) and highest fat content (5.23%) of all. Bi genotype exhibited higher WBSF (53.78, 48.69N), higher cook loss (36.27, 34.32%), higher fat content (2.93, 2.35%), and lower moisture content (73.70, 75.07%) than Bt. Further research is needed to estimate the actual consumer acceptance of beef forequarter muscles and their marketing potential as individual cuts in the Mexican market.

A survey of beef carcass quality and quantity attributes in Mexico

The objective of the present study was to evaluate quality and yield attributes of Mexican beef carcasses to serve as a benchmark for production in the Mexican beef cattle industry. Seven packing plants were surveyed nationwide. Carcass yield and quality traits were assessed in the cooler at approximately 24 h postmortem. Results indicated that around 90% of the beef slaughter population in Mexico has a strong Bos indicus genetic background. Moreover, 71.6% of the surveyed cattle are presented for slaughter at a BW between 400 and 500 kg. Chilled carcass weight was between 220 and 340 kg in 88.9% of the surveyed population. According to European beef carcass grading standards, carcass conformation varied from poor to good in 82% of the carcasses, whereas in 17.8% the conformation was very good or excellent. In 60.7% of the surveyed carcasses the KPH was 2% or less. The subcutaneous fat depth was 1 cm or less in 90% of the carcasses. In 71.8% of the carcasses the LMA was of 80 cm(2) or less, whereas only 8.6% had LMA values of 90 cm(2) or greater. Carcass maturity score USDA B(100) or less was found in 92.4% of the evaluated carcasses, whereas 28.5% were graded as USDA A(100)/B(00). A total of 93.6% of the sample had marbling scores of 300 or less, corresponding to the categories slight, practically devoid, or traces. Only 12.9% of the carcasses exhibited a yellow fat cover. In the remaining 87.1% the fat cover was white or beige. The backfat layer was uniform in 43.2% of the carcasses, whereas 55.9% had an uneven fat cover. Information from this survey provided data that could serve as a means to develop a yield and quality evaluation program that can be further developed into a value system for Mexican beef carcasses and live cattle.

Animal performance and meat quality in cull cows with early weaned calves in Argentina

Early weaning of calves (60 days old) is adopted in cow-calf operations for its high reproductive response. The objective of this research work was to find how age classes are related to beef quality in early weaning cull cows. Twenty four cows were grouped in four different age classes (teeth and number of calves produced) from two teeth and no calf produced, up to 12 years and 7 calves produced. All cows grazed a perennial pasture based on alfalfa and fescue. There were differences (P<0.05) in final weight (younger cows being lighter) but no other differences could be found during field conditions or in abattoir data (carcass weight and yield, top value hindquarter cuts weight and carcass percent). No differences (P>0.05) could be found in meat quality attributes except for moisture, protein and fat yellowness. Differences (P<0.05) in sensory attributes could only be found in connective tissue.