Predicting phenotypes of beef eating quality traits.

Introduction: Phenotype predictions of beef eating quality for individual animals could be used to allocate animals to longer and more expensive feeding regimes as they enter the feedlot if they are predicted to have higher eating quality, and to sort carcasses into consumer or market value categories. Phenotype predictions can include genetic effects (breed effects, heterosis and breeding value), predicted from genetic markers, as well as fixed effects such as days aged and carcass weight, hump height, ossification, and hormone growth promotant (HGP) status. Methods: Here we assessed accuracy of phenotype predictions for five eating quality traits (tenderness, juiciness, flavour, overall liking and MQ4) in striploins from 1701 animals from a wide variety of backgrounds, including Bos indicus and Bos taurus breeds, using genotypes and simple fixed effects including days aged and carcass weight. The genetic components were predicted based on 709k single nucleotide polymorphism (SNP) using BayesR model, which assumes some markers may have a moderate to large effect. Fixed effects in the prediction included principal components of the genomic relationship matrix, to account for breed effects, heterosis, days aged and carcass weight. Results and Discussion: A model which allowed breed effects to be captured in the SNP effects (e.g., not explicitly fitting these effects) tended to have slightly higher accuracies (0.43-0.50) compared to when these effects were explicitly fitted as fixed effects (0.42-0.49), perhaps because breed effects when explicitly fitted were estimated with more error than when incorporated into the (random) SNP effects. Adding estimates of effects of days aged and carcass weight did not increase the accuracy of phenotype predictions in this particular analysis. The accuracy of phenotype prediction for beef eating quality traits was sufficiently high that such predictions could be useful in predicting eating quality from DNA samples taken from an animal/carcass as it enters the processing plant, to enable optimal supply chain value extraction by sorting product into markets with different quality. The BayesR predictions identified several novel genes potentially associated with beef eating quality.

Combining hierarchical clustering and preference mapping differentiates consumer preference for dry aged mutton.

Dry ageing of mutton may enhance mutton's consumer appeal; however, consumer acceptance of mutton is heterogeneous. To identify which consumers prefer dry aged mutton, dry (DA) and wet aged mutton (WA) loin and topside were rated by consumers (n = 540) for tenderness, juiciness, liking of flavour and overall liking on a 0-100 scale. Two predictive liking models were developed, utilising either consumer clusters (identified by agglomerative hierarchical clustering) which related to mutton liking and ageing method preference, or demographic factors. The cluster based model had the highest explanatory power. Cluster 1 (n = 219) preferred DA (p < 0.001), rating it 5.9 points higher than WA, cluster 2 (n = 235) had no ageing method preference (p > 0.05), and cluster 3 (n = 79) preferred WA (p < 0.001), rating WA liking 8.3 points higher than DA. Cluster characterisation identified some differences between clusters that may relate to consumer ethnicity and familiarity with mutton.

European conformation and fat scores of bovine carcasses are not good indicators of marbling.

Marbling is one of the primary carcass attributes utilized in most beef grading systems for eating quality evaluation. In Europe, the current beef grading system is the EUROP grid, which is focused on carcass commercial value and production yield rather than eating quality estimation. The aim of this study was to investigate the relationship between marbling and the most common scores for carcass classification in Europe. If there are strong associations between marbling and European classification scores, marbling score may be estimated from the carcass characteristics. However, this study indicated that European classification scores explain only a slight proportion of the variance in marbling score (32%, 46%, 34% and 21% for the entire cattle group, young bulls, females and steers, respectively). Therefore, whereas the EUROP grid is well adapted to estimate yield, it does not reflect marbling at all. The European beef industry should take into account additional indicators related to beef palatability to assist the determination of the commercial value of carcasses.

Contributions of tenderness, juiciness and flavor liking to overall liking of beef in Europe.

This study evaluated the contributions of sensory traits to overall liking in Europe. Perceptions by untrained consumers of tenderness, juiciness, flavor liking and overall liking were determined using the Meat Standards Australia protocols. According to European consumer testing with European beef samples, flavor liking was the most important contributor (39%) to beef overall liking, followed by tenderness (31%) and juiciness (24%) (P < .05; R2 > 0.94). The improvement in tenderness over the last decades may explain the highest contribution of flavor liking nowadays. Flavor liking is therefore the main driver of variability in overall liking. Juiciness is the least robust trait which could be influenced by other traits during consumer perception. For outstanding steaks, each sensory trait should have excellent scores and high contributions to overall liking. For medium cuts, one sensory trait with a low score has the potential to be compensated by other traits with higher scores and more emphasis will be placed on the trait with the lowest perception.

Beef Quality Preferences: Factors Driving Consumer Satisfaction.

The current study was designed to broaden the understanding of the attributes impacting the sensory properties of beef when consumed. Using a survey of consumers from three different geographical regions in the United States (US), we determined the impacts of three attributes on overall satisfaction in several different ways. The two main statistical methods used were an Ordinary Least Squares (OLS) model and the Conditional Logit model. Perhaps the most important finding of this study was that flavor was the largest contributor to consumer satisfaction. This finding was consistent throughout all the models. In the base model, flavor represented 59% of the satisfaction rating. Additionally, results indicated domestic beef was preferred over Australian beef by US consumers. Another important finding of the study was the impact of the demographic variables of age, income, and gender on satisfaction. The older group generally placed more emphasis on tenderness, while younger people preferred juicier beef. Males were more responsive than females for all attributes, especially tenderness. Those with higher income were more responsive to tenderness for all quality levels, but the lower income group was more responsive to juiciness. Overall, flavor had the largest impact on consumers' satisfaction level in comparison to tenderness or juiciness.

Exploring Consumer Palatability of Australian Beef Fajita Meat Enhanced with Phosphate or Sodium Bicarbonate.

The objective of this study was to determine the consumer eating quality of five Australian beef muscles (outside skirt/diaphragm, inside skirt/transversus abdominis, inside round cap/gracilis, bottom sirloin flap/obliquus abdominis internus, and flank steak/rectus abdominis) served as fajita strips. All the muscles were divided in half and enhanced (12%) with a brine solution containing either phosphate, a "clean label" ingredient sodium bicarbonate, or not enhanced. Muscle and enhancement independently influenced (P < 0.01) tenderness, juiciness, flavor, and overall liking. Overall, the bottom sirloin flap was liked the most (P < 0.05) when compared with all the other muscles, while the inside round cap was liked less but did not differ (P > 0.05) from the inside skirt or flank steak. Samples enhanced with sodium bicarbonate were the most (P < 0.05) tender and juicy; samples enhanced with phosphate were intermediate, and the control samples were the least tender and juicy, regardless of the muscle. Flavor and overall liking were similar (P > 0.05) between clean and phosphate-enhanced samples, and both were liked more than the control samples. Enhancement was necessary for acceptable eating quality of all the muscles evaluated in this study; however, the inside round cap was the least suitable. These results indicate that a "clean label" enhanced fajita product is possible without compromising cooking yield or consumer satisfaction.

Extending Aging of Beef Longissimus Lumborum From 21 to 84 Days Postmortem Influences Consumer Eating Quality.

Our objective was to determine the effect of extending postmortem aging from 21 to 84 days on consumer eating quality of beef longissimus lumborum. Strip loins were collected from 108 carcasses. The longissimus lumborum muscle was isolated from strip loins and assigned to one of ten postmortem aging periods from 21 to 84 days (7-day increments) and balanced within four anatomical positions within the muscle. Consumer evaluations for tenderness, juiciness, flavor, and overall liking were conducted using untrained consumer sensory panels consisting of 1080 individual consumers, in accordance with the Meat Standards Australia protocols. These scores were then used to calculate an overall eating quality (MQ4) score. Postmortem aging had no effect (P > 0.05) on tenderness, but juiciness, flavor liking, overall liking, and MQ4 declined (P < 0.05) as aging period increased. Samples aged 21 to 42 days were most preferred having greater (P < 0.05) overall liking and greater (P < 0.05) MQ4 scores than samples aged 70 to 84 days postmortem. These results suggest that longissimus lumborum samples should not be wet-aged longer than 63 days to prevent potential negative eating experiences for consumers; however, altering storage conditions, specifically reducing temperature, could potentially allow for longer chilled storage without such negative effects on flavor and overall liking.

Polish consumer categorisation of grilled beef at 6 mm and 25 mm thickness into quality grades, based on Meat Standards Australia methodology.

Meat Standards Australia (MSA) methodology was used to evaluate the sensory categorization of beef by Polish consumers. A significant quality range was created by utilisation of 3 muscles, M. psoas major, M. longissimus thoracis et lumborum, and M. semimembranosus from 22 divergent bull carcasses (Holstein-Friesian crosses with Limousine, Hereford). Consumers evaluated every sample for selected sensory traits and chose a grade. A trend was observed for 6 mm preparation to reduce the proportion of unsatisfactory SM, with a consequent increase in 3star counts, in contrast to reducing the proportion of PM 5star and LTL 4star with an increase in the lower categories. Within each thickness Polish consumers clearly distinguished between grades, defined by MQ4 (Meat Quality, 4 variables) boundaries derived from discriminant analysis. Similar accuracy was achieved for both thicknesses. It was concluded that the MQ4 score could be successfully used to support a meat quality grading system in Poland.

Effects of different ageing methods on colour, yield, oxidation and sensory qualities of Australian beef loins consumed in Australia and Japan.

This study investigated the effect of three ageing methods (dry, wet and stepwise wet-then-dry) and ageing time on pH, colour, yield, lipid and protein oxidation and eating quality of beef loins using Meat Standards Australia (MSA) sensory protocols with 900 and 540 consumers in Australia and Japan, respectively. Australian beef loins (Longissimus thoracis et lumborum) at four days post mortem were subjected to wet ageing (boneless; for 7, 21, 35 or 56 days), dry ageing (bone-in; for 35 or 56 days) or a wet-then-dry ageing method (bone-in; 21 days wet ageing followed by 35 days dry ageing). The pH was higher in dry aged than wet aged beef loins (P < .001). Instrumental measurement of surface colour of trimmed dry and wet aged steaks showed significant differences in a*, b* and hue angle. Weight loss was higher in dry aged primals (P < .001), however, total water content was similar among the two ageing methods (P = .934). Retail yield did not differ between 35 and 56 days dry aged primals. Lipid (TBARS) and protein (total carbonyl content) oxidation between the dry and wet aged samples differed depending on the ageing time. When comparing the wet-then-dry and 56 days dry aged samples, only pH and retail yield differed. Australian and Japanese consumers rated dry aged steaks significantly higher (P < .001) than the wet aged counterparts for tenderness, juiciness, flavour, overall liking and weighted palatability scores. The wet-then-dry steaks were also rated higher than the 56 days wet aged steaks for flavour, overall liking and palatability within the Japanese sensory panels. The Japanese consumers also consistently rated all MSA sensory attributes lower (P < .001) than the Australian consumers. The results from this study show dry ageing provides a value adding opportunity for the meat industry in both domestic and export markets.

The Impact of Pre-Slaughter Stress on Beef Eating Quality.

The study evaluated the relationship between pre-slaughter stress, plasma biomarkers and consumer-evaluated eating quality of pasture raised beef cattle (n = 488). The design tested steer only, heifer only and mixed sex cattle with a comparison of direct kill versus a 14 day rest period in abattoir holding paddocks prior to slaughter. Experiment One sourced cattle from four farms and tested shipping and road transport. Experiment Two sourced cattle from four farms and tested a commercial saleyard pathway. The impact on treatment on untrained consumer eating quality scores were tested on five muscle groups, m. psoas major, m. longissimus dorsi lumborum, m. biceps femoris, m. semitendinosis, and m. infraspinatus. Across all muscles, a two-week rest period had the biggest improvement in sensory score. Mixed groups scored lower in the outside muscle than non-mixed groups. However, the mixing response was inconsistent in the eye round muscle and not significant in the other muscles. Plasma glucose and L-lactate indicated a marked acute stress response at slaughter with a small detrimental impact on consumer score. The muscle damage enzyme markers creatine kinase (CK) and aspartate aminotransferase (AST) were strongly associated with a lower meat quality score (MQ4). Neither ß-hydroxybutyrate (ßHB) nor non-esterified fatty acids (NEFA) were associated with MQ4, suggesting that fat mobilisation does not impact consumer sensory score.

Influence of Kiwifruit Extract Infusion on Consumer Sensory Outcomes of Striploin (M. longissimus lumborum) and Outside Flat (M. biceps femoris) from Beef Carcasses.

Actinidin is a cysteine protease enzyme which occurs in kiwifruit and has been associated with improved tenderness in red meat. This study evaluated the impact of actinidin, derived from kiwifruit, on consumer sensory outcomes for striploin (M. longissimus lumborum) and outside flat (M. biceps femoris). Striploins and outside flats were collected from 87 grass-fed steers. Carcasses were graded to the Meat Standards Australia (MSA) protocols. Striploins and outside flats were then dissected in half and allocated to one of the following two treatments: (1) not infused (control) and (2) infused with a kiwifruit extract (enhanced), and then prepared as grill and roast samples. Grill and roast samples were then aged for 10 or 28 days. Consumer evaluations for tenderness, juiciness, flavor, and overall liking were conducted using untrained consumer sensory panels consisting of 2080 individual consumers, in accordance with the MSA protocols. These scores were then used to calculate an overall eating quality (MQ4) score. Consumer sensory scores for tenderness, juiciness, flavor, overall liking, and MQ4 score were analyzed using a linear mixed-effects model. Kiwifruit extract improved consumer scores for tenderness, juiciness, flavor, overall liking, and MQ4 scores for striploins and outside flat (p < 0.05). These results suggest that kiwifruit extract provides an opportunity to improve eating experiences for consumers.

The Use of Biochemical Measurements to Identify Pre-Slaughter Stress in Pasture Finished Beef Cattle.

This study considered the relationship between pre-slaughter stressors and plasma biomarkers in 488 pasture-raised cattle across two experiments. The design aimed to test groups consisting of steer only, heifer only, and mixed sex cattle under direct kill versus rested (14 days in abattoir holding paddocks) protocols. In Experiment One, cattle were sourced from four farms, and transported by trucks and ships on the same day. In Experiment Two, cattle were sourced from four farms where a comparison was made between marketing via two commercial saleyards or direct farm gate consignment to abattoir. Blood samples were collected at exsanguination for subsequent analyses and relation to meat quality attributes. Muscle damage, as indicated by creatine kinase, is the biomarker most correlated to ultimate pH and muscle glycogen concentrations. A two-week rest period is effective for lowering this enzyme and improving muscle glycogen concentration. Although the cattle was subjected to a range of stress inducing treatments, we found that plasma biomarkers alone appeared insufficient for use as diagnostic stress indicators.

Do demographic and beef eating preferences impact on South African consumers' willingness to pay (WTP) for graded beef?

A total of 720 South African consumers sourced from rural and urban backgrounds scored willingness to pay (WTP) for different eating quality grades of beef. The consumers had previously participated in taste panels which scored eating quality of grilled and slow cook samples before grading them as either 2 (unsatisfactory), 3 (good every day), 4 (better than everyday), or 5 (premium) star quality. Consumers provided details on demographic and meat preference traits. Eating quality grade had the largest effect on WTP (P < .001). Whether consumers were sourced from urban or rural backgrounds, or had tasted beef prepared using grill or slow cook methods had little effect on WTP (P > .05). Similarly, demographic and meat preference traits had little effect of WTP (P > .05), with the exception that at the higher meat quality grades older consumers had a lower WTP than younger age groups (P < .05), as did households with >8 adult consumers (P < .05).

Do extended transport times and rest periods impact on eating quality of beef carcasses?

The experiment tested the effect of four extended transport treatments on sensory and objective meat quality in beef. A total of 343 steers (88 steers from each of three properties and 79 from a fourth property) were allocated to four treatments including a 12 hour transport time (T12), 24 hour transport time (T24), 24 h as 12 hour transport time, a 12 hour rest, with a further 12 hour transport (T12 ~ T12), 36 hour transport treatment (T36). Within property departure times of treatments were staggered to arrive at the abattoir together. There were no significant transport effects (P > .05) on live animal, carcass traits, consumer sensory scores, and objective meat quality of the longissimus lumborum. There was large between property variation in the proportions of carcasses excluded from grading on the basis of low ribfat, high ultimate pH and dark meat color scores. Variation in these traits was not associated with transport treatments and was likely related to variation in on-farm factors.

Impact of high oxygen and vacuum retail ready packaging formats on lamb loin and topside eating quality.

Lamb steaks from semimembranosus (SM) and longissimus thoracis et lumborum (LTL) muscles were allocated to three different packaging treatments - Darfresh® vacuum skin packaging (VSP), Darfresh® Bloom packaging (80% O2:20% CO2; Hi-Ox-DB) or high oxygen modified atmosphere packaging (80% O2:20% CO2; Hi-Ox-MAP) - and stored in simulated retail display for 5 or 10days and then subjected to consumer sensory and chemical analyses. Hi-Ox-MAP and Hi-Ox-DB samples had lower tenderness, flavor, juiciness and overall liking scores and higher TBARS values, compared to VSP. Hi-Ox-MAP samples deteriorated in juiciness and flavor between 5 and 10days. Hi-Ox-MAP LTL samples had a lower myofibrillar fragmentation index, consistent with reduced proteolysis, although desmin proteolysis and desmin and troponin-T cross-linking were not influenced by packaging. The LTL exhibited greater desmin degradation and reduced desmin cross-linking relative to the SM, supporting the higher tenderness scores in this muscle. Direct packaging of lamb into retail ready VSP may provide the sheepmeat industry with greater flexibility while increasing consumer satisfaction.

A comparison of Japanese and Australian consumers' sensory perceptions of beef.

This paper presents a comparison of Japanese and Australian consumer sensory responses to beef, based on Meat Standards Australia methodology. Japanese and Australian consumers evaluated paired beef samples according to four sensory traits, and the weighted results were combined to produce a Meat Quality score (MQ4). The consumers also categorized the beef samples to one of four grades (unsatisfactory, good everyday, better than everyday and premium). The proportion of samples assigned to each grade was similar for Japanese and Australian consumers for yakiniku and shabu shabu cooking methods; however, Japanese consumers assigned lower scores to the grill samples. In terms of the MQ4 boundary scores between grades, these were very similar for both Japanese and Australian consumers across all cooking methods. In terms of the weightings for the four sensory traits, juiciness was more important for Japanese consumers than Australian for grill and shabu shabu cooking methods. Flavor had the highest weighting for both consumer groups. This study showed that a beef description system based on the MQ4 score, with some adjustments to the weightings and cut-off values, could be useful in describing the eating quality of beef for the Japanese consumer.

Modelling of beef sensory quality for a better prediction of palatability.

Despite efforts by the industry to control the eating quality of beef, there remains a high level of variability in palatability, which is one reason for consumer dissatisfaction. In Europe, there is still no reliable on-line tool to predict beef quality and deliver consistent quality beef to consumers. Beef quality traits depend in part on the physical and chemical properties of the muscles. The determination of these properties (known as muscle profiling) will allow for more informed decisions to be made in the selection of individual muscles for the production of value-added products. Therefore, scientists and professional partners of the ProSafeBeef project have brought together all the data they have accumulated over 20 years. The resulting BIF-Beef (Integrated and Functional Biology of Beef) data warehouse contains available data of animal growth, carcass composition, muscle tissue characteristics and beef quality traits. This database is useful to determine the most important muscle characteristics associated with a high tenderness, a high flavour or generally a high quality. Another more consumer driven modelling tool was developed in Australia: the Meat Standards Australia (MSA) grading scheme that predicts beef quality for each individual muscle×specific cooking method combination using various information on the corresponding animals and post-slaughter processing factors. This system has also the potential to detect variability in quality within muscles. The MSA system proved to be effective in predicting beef palatability not only in Australia but also in many other countries. The results of the work conducted in Europe within the ProSafeBeef project indicate that it would be possible to manage a grading system in Europe similar to the MSA system. The combination of the different modelling approaches (namely muscle biochemistry and a MSA-like meat grading system adapted to the European market) is a promising area of research to improve the prediction of beef quality. In both approaches, the volume of data available not only provides statistically sound correlations between various factors and beef quality traits but also a better understanding of the variability of beef quality according to various criteria (breed, age, sex, pH, marbling etc.).