Breeding schemes with optimum-contribution selection or truncation selection for beef cattle destined for use on dairy females

We tested the hypothesis that the size of a beef cattle population destined for use on dairy females is smaller under optimum-contribution selection (OCS) than under truncation selection (TRS) at the same genetic gain (ΔG) and the same rate of inbreeding (ΔF). We used stochastic simulation to estimate true ΔG realized at a 0.005 ΔF in breeding schemes with OCS or TRS. The schemes for the beef cattle population also differed in the number of purebred offspring per dam and the total number of purebred offspring per generation. Dams of the next generation were exclusively selected among the one-year-old heifers. All dams were donors for embryo transfer and produced a maximum of 5 or 10 offspring. The total number of purebred offspring per generation was: 400, 800, 1,600 or 4,000 calves, and it was used as a measure of population size. Rate of inbreeding was predicted and controlled using pedigree relationships. Each OCS (TRS) scheme was simulated for 10 discrete generations and replicated 100 (200) times. The OCS scheme and the TRS scheme with a maximum of 10 offspring per dam required approximately 783 and 1,257 purebred offspring per generation to realize a true ΔG of €14 and a ΔF of 0.005 per generation. Schemes with a maximum of 5 offspring per dam required more purebred offspring per generation to realize a similar true ΔG and a similar ΔF. Our results show that OCS and multiple ovulation and embryo transfer act on selection intensity through different mechanisms to achieve fewer selection candidates and fewer selected sires and dams than under TRS at the same ΔG and a fixed ΔF. Therefore, we advocate the use of a breeding scheme with OCS and multiple ovulation and embryo transfer for beef cattle destined for use on dairy females because it is favorable both from an economic perspective and a carbon footprint perspective.     

Dietary α-Tocopheryl Acetate Enhances Beef Quality in Holstein and Beef Breed Steers

The effect of long-term feeding (252 days) of three supplemental levels of α-tocopheryl acetate (actual 0, 360 and 1290 IU/head/day) on meat quality was evaluated in Holstein and beef breed steers. Tissue vitamin E concentrations were increased by each increment of supplementation. The color display life of fresh beef under simulated retail conditions was extended 2 to 5 days by vitamin E and lipid oxidation was markedly reduced. Microbial population was not affected by level of supplementation. No deterioration in sensory quality occurred for steaks from supplemented steers that were displayed until the time steaks from unsupplemented steers discolored.     

Volatile Compounds of Raw Beef from 5 Local Spanish Cattle Breeds Stored Under Modified Atmosphere

Volatile compounds of raw beef from Asturiana de los Valles, Morucha, Parda Alpina, Pirenaica, and Retinta cattle breeds were studied. Steaks were packaged under 60% O₂, 30% CO₂, and 10% N₂, and 53 volatile compounds were tentatively identified by purge‐and‐trap extraction and gas chromatography with mass spectrometry after 0, 5, 10, and 15 d of chill storage. The degradation of beef quality with increasing storage time was evidenced by the increase in 2,3,3‐trimethylpentane, 2,2,5‐trimethylhexane, 3‐octene, 3‐methyl‐2‐heptene, 2‐octene, and 2‐propanone and by the decrease in dimethyl sulfide. Consequently, some of the volatile compounds, which are believed to be formed by thermal degradation of meat, might be formed during chill storage, and the rate of formation of some was dependent on the specific compound.     

Effect of nisin on the storage of sous vide processed Korean seasoned beef

Seasoned beef called Jangzorim in Korea is produced by boiling in soy sauce, and is a popular food in Korea. The aim of this study is to evaluate the microbial safety and physical qualities of sous vide processed seasoned beef, and the effect of nisin during storage. Sous vide processed packages with or without nisin (100 IU or 500 IU) were stored at 4 °C or 25 °C for 60 days, and samples measured for quality at regular intervals throughout this storage period. In the case of 25 °C storage, the number of mesophilic microorganisms in seasoned beef packages without nisin increased markedly, but with nisin there was no observed increase. Psychrotrophic microorganisms, anaerobic microorganisms, and B. cereus cells showed similar trends, although C. perfringens was not detected in all samples. At 25 °C storage, changes in the cutting force of packages containing nisin showed no significant change, packages without nisin decreased markedly. The colour of packages without nisin showed a drastic decrease in lightness (‘L’) while no changes were observed in packages with nisin.     

Heat resistance of Escherichia coli O157:H7 in cook‐in‐bag ground beef as affected by pH and acidulant†

Summary The heat resistance of a four‐strain mixture of Escherichia coli O157:H7 was tested. The temperature range was 55–62.5 °C and the substrate was beef at pH 4.5 or 5.5, adjusted with either acetic or lactic acid. Inoculated meat, packaged in bags, was completely immersed in a circulating water bath and cooked to an internal temperature of 55, 58, 60, or 62.5 °C in 1 h, and then held for pre‐determined lengths of time. The surviving cell population was enumerated by spiral plating meat samples on tryptic soy agar overlaid with Sorbitol MacConkey agar. Regardless of the acidulant used to modify the pH, the D ‐values at all temperatures were significantly lower (P < 0.05) in ground beef at pH 4.5 as compared with the beef at pH 5.5. At the same pH levels, acetic acid rendered E. coli O157:H7 more sensitive to the lethal effect of heat. The analysis of covariance showed evidence of a significant acidulant and pH interaction on the slopes of the survivor curves at 55 °C. Based on the thermal‐death–time values, contaminated ground beef (pH 5.5/lactic acid) should be heated to an internal temperature of 55 °C for at least 116.3 min and beef (pH 4.5/acetic acid) for 64.8 min to achieve a 4‐log reduction of the pathogen. The heating time at 62.5 °C, to achieve the same level of reduction, was 4.4 and 2.6 min, respectively. Thermal‐death–time values from this study will assist the retail food processors in designing acceptance limits on critical control points that ensure safety of beef originally contaminated with E. coli O157:H7.     

Fabricated Beef Product: Effect of Handling Conditions on Microbiological, Chemical, and Sensory Properties

Total microbial count was not adversely affected by lowering the holding temperature of fabricated beef roast from 60°C to 54°C or by 12 hr holding time. If a reduction in holding temperature is anticipated, then initial roast contamination and sanitation of the food facility are of critical importance. A stabilizing period of 20 min at room temperature (～23°C) did not decrease yield, but caused a slight lowering of sensory scores. Tenderness was more acceptable in product held at 54°C compared to 60°C. In general, all sensory evaluation ratings were slightly lower with increased holding time.     

Glucose and Internal Cooking Temperature Effects on Low Fat, Pre- and Post-Rigor, Restructured Beef Roasts

Muscles were excised pre-rigor (hot-boned, HB) or post-rigor (conventionally boned, CB), chunked, and were subjected to four ingredient treatments: (SPE) 2% NaCl, 0.5% NaCl, 0.5% phosphate, 2% glucose (SP 2% NaCl, 0.5% phosphate (SG) 2% NaCl, 2% glucose and (PG) 0.5% phosphate, 2% glucose to produce low fat, restructured, beef roasts, which were cooked to an internal temperature of 63 or 93°C. Addition of glucose to a salt and phosphate (LEM-O-FOS¹) ingredient treatment as well as cooking to 93°C helped maintain low warmed-over flavor (WOF) scores and kept thiobarbituric acid values below threshold (< 1.0) while maintaining desirable consumer acceptability scores.     

Contribution of Lactobacillus plantarum and Leuconostoc mesenteroides subsp. mesenteroides to Atypical Odors of Beef Strip Loins

Sterile beef strip loin tissue was inoculated with Lactobacillus plantarum or Leuconostoc mesenteroides subsp. mesenteroides, placed in sterile sample bottles which were purged with CO₂, and stored up to 28 days at 3°C. Volatile compounds detected in the headspace of these samples included acetone, toluene, acetic acid, ethyl acetate, a C₇ hydrocarbon, and trichloromethane. The profile of volatiles in packaged sterile loin tissue stored for up to 28 days was similar. However, the inoculated samples spoiled (soured) at a faster rate.     

Dissimilarity scaling and INDSCAL analysis in the study of flavour differences between normal pHu and DFD beef

Overall dissimilarity measurement of paired stimuli followed by Individual Differences Scaling (INDSCAL) analysis was used to study flavour perception in a set of beef extracts. The experiment was designed to determine whether pH contributed to flavour difference between beef of “normal” ultimate pH (pHu5.8) and “dark-cutting” (DFD) beef (pHu6.2). Assessors distinguished the flavour of “normal” pHu and DFD beef both by a combination of pH and titratable acidity, and a second dimension independent of pH. The chemicals added to adjust pH independently of the original muscle composition contributed a third flavour dimension. Substantial assessor variation was observed in the relative weight given to the three flavour dimensions, and this is discussed in relation to the task of judging overall dissimilarity.     

The geographies of a more just food system: Building landscapes for social reproduction

Within the lifetime of a generation of people now involved in work in the cattle and beef industry in South Dakota, the landscapes of social reproduction that support and give shape to life for people there have been rearranged. Many of the social and physical relationships that developed to support smaller-scale, diverse farms and their surrounding communities are being made redundant by a new system of beef production and retailing. The costs of these redundancies are felt in dwindling small towns and an ever sparser rural population. Considering these changes as parts of landscapes of social reproduction is a means to connect the political and corporate logic driving our food systems to the spatial production of difference in the conditions for livelihood, as well as the spatial production of livelihood itself for both producers and consumers. Such an analysis is necessary in order to address the injustices inherent within our current food system.