Ray Watson

Consumer assessment of eating quality – development of protocols for Meat Standards Australia (MSA) testing

Meat Standards Australia sought a consistent measure of the beef eating experience to the consumer. Rather than objective measurements or trained panel sensory assessment, it was decided to proceed with direct consumer assessment. Consumer-based assessment has much greater variation, but it has the decided advantage of validity. This paper summarises the path taken to obtain consistent consumer assessment. What meat samples to present to consumers? What responses to ask for? What to do with these responses when they were obtained? The answers to these questions have led to the MQ4 measure of consumer assessment of meat eating quality, which now forms the basis of the MSA predictive model.

Evolution of the Meat Standards Australia (MSA) beef grading system

The Australian Beef Industry identified variable eating quality as a major contributor to declining beef consumption in the early 1990s and committed research funding to address the problem. The major issue was the ability to predict the eating quality of cooked beef before consumption. The Meat Standards Australia (MSA) program developed a consumer testing protocol, which led to MSA grading standards being defined by consumer score outcomes. Traditional carcass grading parameters proved to be of little value in predicting consumer outcomes. Instead a broader combination of factors forms the basis of an interactive prediction model that performs well. The grading model has evolved from a fixed parameter ‘Pathway’ approach, to a computer model that predicts consumer scores for 135 ‘cut by cooking method’ combinations for each graded carcass. The body of research work conducted in evaluating critical control points and in developing the model predictions and interactions has involved several Australian research groups with strong support and involvement from the industry.

Development of the Meat Standards Australia (MSA) prediction model for beef palatability

In this paper, the statistical aspects of the methodology that led to the Meat Standards Australia (MSA) prediction model for beef palatability are explained and described. The model proposed here is descriptive: its intention is to describe the large amounts of data collected by MSA. The model is constrained to accord with accepted meat science principles. The combined dataset used in development of the prediction model reported is around 32 000 rows × 140 columns. Each row represents a sample tasted by 10 consumers; each column specifies a variable relating to the sample tested. The developed model represents the interface between experimental data, scientific evaluation and commercial application. The model is used commercially to predict consumer satisfaction, in the form of a score out of 100, which in turn determines a grade outcome. An important improvement of the MSA model relative to other beef grading systems is that it assigns an individual consumer-based grade result to specific muscle portions cooked by designated methods; it does not assign a single grade to a carcass.

Effects of hormonal growth promotants (HGP) on growth, carcass characteristics, the palatability of different muscles in the beef carcass and their interaction with aging

Effects of hormonal growth promotant (HGP) implantation on liveweight, carcass and meat quality measurements were examined using 80 Angus yearling cattle. After entry to the feedlot, 40 steers and 40 heifers were implanted with Revalor-S (28mg oestradiol and 140mg trenbolone acetate) and Revalor-H (20mg oestradiol, 200mg trenbolone acetate), respectively. Cattle were slaughtered after 55 and 65 days on feed. Samples from the Mm. longissimus dorsi,bicepsfemoris(thecapandbodyportions),gluteusmedius(theeyeandDportions),infraspinatusandtricepsbrachii werepreparedforsensorytestingafteragingfor5and21daysafterslaughter.Atotalof854musclesampleswerecookedby grill (601) or roast (253) methods and served to consumers using the Meat Standards Australia taste panel protocols. Whenadjustedtothesameinitialliveweight,implantationwithRevalor-HandRevalor-Sresultedina4and7%increase in slaughter weight, respectively. Implantation resulted in an increased ossification score in steers (P <0.05), but not in heifers. Therewas asignificantinteraction(P <0.05) betweenHGPimplantation anddaysaged forshearforce.There wasa small effect of HGP implants on compression (P <0.05), but not on cook loss and intramuscular fat percentage. Muscles differed in their response to HGP implantation (P <0.05) for tenderness, overall liking and palatability scores. Muscles also differedintheiragingratesafterslaughter(P <0.05).ThegreatestresponseinsensoryscorestoHGPimplantationwasfound in those muscles that had the highest aging rates. Possible mechanisms by which muscles differed in their response to HGP implantation are discussed.

Meta-analysis of the published effects of HGP use on beef palatability in steers as measured by objective and sensory testing

Evidence is presented that suggests strongly that hormone growth promotant (HGP) implantation has a negative effect on beef palatability. This is based on a meta-analysis of results reported in refereed papers that have appeared in the meat-science literature. To be included in this analysis, a paper must have reported results for control samples (no HGP) and treatment samples (HGP) for either objective testing (Warner-Bratzler shear-force) or consumer preference (tenderness score). The paper must also have reported estimates and standard errors. Further, we consider only the case of steers, and the M. longissimus dorsi (striploin). While most of these studies yielded non-significant differences, most gave an estimate indicating that the HGP treatment had a negative effect on beef palatability. When these results are combined using a meta-analysis, they provide significant evidence that the use of HGP implants negatively influences palatability.

On the size of a rumour

Two rumour models are considered, the first due to Daley and Kendall (1965) and the second due to Maki and Thompson (1973). The size of a rumour, defined as the number of individuals in the population eventually hearing the rumour, is investigated using both deterministic and stochastic approximations, and some asymptotic distributional results for the size distribution for the two models are obtained and compared.

Current usage and future development of the Meat Standards Australia (MSA) grading system

Progress in the development and adoption of the Meat Standards Australia system has encouraged substantial change and an improved consumer awareness at all points of the Australian beef production chain. The system is moving from niche to mainstream market application with the exciting potential to transform many industry practices and build a more direct consumer focus. The system aims to accurately predict consumer satisfaction levels for individual cooked beef portions. This is a major advance on grading systems that classify carcasses into groups of like appearance. A prediction model was developed based on consumer testing and has proved to be useful in categorising a wide range of beef into consumer grades within cooking methods. These provide a basis to ensure a predictable eating quality result for the consumer and a mechanism to align product description and pricing throughout the production chain. When used in value-based marketing systems financial reward can be directly linked to consumer satisfaction encouraging a consumer-focussed industry. Research is proceeding to extend and improve the accuracy of the prediction model encompassing additional cattle types and cooking methods. Several projects in other countries are adding insights into the relative response of consumers from varied cultural backgrounds. It is hoped that further international collaboration will facilitate use of the developed technology to improve consumer value and industry returns through improved product consistency in global markets.

Japanese consumer categorisation of beef into quality grades, based on Meat Standards Australia methodology

The objective was to evaluate the sensory categorisation of beef by Japanese consumers, based on Meat Standards Australia methodology. Various cuts of beef, with a wide range of quality (from Australian and Japanese cattle) and three cooking methods (grill, yakiniku, shabu shabu), were evaluated by 1620 Japanese consumers in Tokyo and Osaka. Consumers rated each sample for four sensory attributes (tenderness, juiciness, flavor and overall satisfaction), then selected one of four grades (unsatisfactory/2-star, good everyday/3-star, better than everyday/4-star, and premium quality/5-star), based on the quality of the beef within each cooking method. Meat quality scores, denoted as MQ4 scores (weighted combination of the four sensory attributes) were calculated from the Japanese consumer test results, to describe the Japanese consumer rating of beef. The distribution of the Japanese consumer MQ4 scores showed a clear distinction between grades, with the majority of scores being included within the boundaries of each grade. The MQ4 score allocated approximately 64% of the samples to their correct consumer grades. The MQ4 score showed potential to be used as a tool in developing and monitoring a consumer-focused grading system that is able to predict Japanese consumer satisfaction of individual beef cuts prepared by different cooking methods.

An application of a martingale central limit theorem to the standard epidemic model

In this paper, useful limit results for the standard epidemic model are proved using a martingale central limit theorem given by McLeish [2]. These results do not depend on the solutions of the deterministic equations, and also cover the case of a small initial number of infectives. Further, the results find immediate application in approximating the size distribution and in estimating the threshold parameter.

Effect of repeated implants of oestradiol-17b on beef palatability in Brahman and Braham cross steers finished to different market end points

The effect of repeated implantation with 20mg oestradiol-17b (Compudose 100) on carcass and meat quality traits was investigated using 478Bos indicusandB. indicus ·Bos tauruscross steers finished on either pasture or grain to achieve carcass weight for one of three market end points (domestic, 220kg; Korean, 280kg; or Japanese, 340kg). In the oestradiol-17b treatment group, animals were administered implants at ~100-day intervals, with the number of implants administered to any steer ranging from one to eight. Cattle were slaughtered and at boning the anterior portion of the M. longissimus lumborum was removed and frozen after aging for 1 day for later objective meat quality measurements (shear force, compression and cook loss %). The adjoining portion was aged for 14 days before consumer sensory testing using the Meat Standards Australia protocols. Each sample was scored for tenderness, juiciness, like flavour and overall liking by 10 untrained consumers. Implanting increased carcass weights and ossification scores (P 0.05) on sensory scores, or objective meat tenderness.