Does the consumer really pick up feeding system differences in beef quality and sensory attributes?
Beef cattle in general are either fed in feedlots on a grain-based diet or raised on veld with or without supplementation. Feedlot animals are normally younger animals and are often supplemented with the beta-agonist, zilpaterol. Zilpaterol is used to enhance growth performance and produce larger carcasses. Most carcasses from animals slaughtered out of feedlots are classified in the A-age class (0 incisors), whereas most veld-raised animals are older animals with 1 – 2 and 3 – 6 permanent incisors, and are therefore classified as AB and B- age, respectively. Production system, and other production factors may influence meat quality, therefore sensory attributes, and ultimately consumer acceptability of meat. Consumer preferences are related to visual appearance (e.g. colour, packaging, fatness and purge) before consumption and perception of texture, aroma and flavour during consumption. The red meat classification system is based primarily on animal age and fatness and has therefore been criticised as satisfying only the requirements of meat sellers without providing the consumer with any measure of expected eating quality. As a result, in the study by the authors cited below, the combined effects of feeding regime accompanied by differences in animal age as well as the utilisation of zilpaterol in a feedlot has been investigated. But because age, feeding regime and beta-agonists may affect meat quality parameters of different muscle types differently, the researchers used three economically important muscles of the beef carcass, i.e. longissimus lumborum, semitendinosus and biceps femoris.
In the study, 80 Bonsmara steers consisting of 20 each of A-age (0-tooth) grain-fed and grain-fed supplemented with zilpaterol, as well as 20 each of grass-fed AB (1-2 teeth) and B-age (3 – 6 teeth) steers were used. After slaughter, the longissimus lumborum, semitendinosus and biceps femoris muscles were dissected and tested for colour, moisture properties, lipid oxidation and sensory attributes.
The results showed that diet in combination with animal age influenced meat colour. Muscles of the older grass-fed steers were generally darker and duller (darker red) compared to muscles of young grain-fed animals. Moisture loss was consistently higher in zilpaterol supplemented meat samples compared to the feedlot controls, while muscles of the grass-fed animals had lower moisture loss. A sensory panel clearly distinguished between cuts of grain-fed and grass-fed carcasses (AB and B) because of flavour characteristics. The AB and B cuts scored higher for grassy, animal-like and rancid flavour overtones and lower for roasted flavour and sourness than grain-fed cuts. This indicated that typical flavours related to diet define expected eating quality.
In summary one should realize that meat quality is a complex and multivariate characteristic which is influenced by the tested factors, but also other interacting factors. Zilpaterol enhances production efficiency in the feedlot, however, this study showed that this is achieved at the expense of some meat quality attributes and therefore eating satisfaction. High moisture loss and poor meat colour in the zilpaterol treatment are attributes which have a negative influence on the decision of consumers to purchase beef. Poor water-holding capacity negatively affects tenderness and juiciness of meat. It is, therefore, important that when optimising productivity, meat quality, hence eating quality should be taken into consideration. Animal age alone could not show clear differences in meat quality, but in combination with feeding system it did in most of the parameters measured. However, because consumer perceptions and preferences differ and there are other interacting factors, the results also suggested that no single feeding system can satisfy their eating experience. In general, the authors concluded that variability in beef and eating quality still exist amongst different feeding systems and if the purpose of the classification system is to describe and identify differences in the product that will relate to consumer experience, a pro-active quality control system is needed to avoid variability. Nevertheless, negative effects of different production systems as described are maybe less likely noticed by consumers unless there is consumer education towards what should be regarded as important.
E. Moholisa, P.E. Strydom, I. Van Heerden & A. Hugo, 2019. Influence of feeding systems on selected beef quality and sensory attributes. S. A. J. Anim. Sci. 49, 1158-1173.