The prevalence of high rigor mortis temperature beef carcasses at abattoirs across South Africa

Abstract

High rigor mortis temperature carcass conditions occur when the pH drops below 6.0 while the temperature is still above 35ﹾC. The aim of this research was to find out if there is an increase in the prevalence of high rigor mortis temperature carcasses in abattoirs across South Africa (SA). With the increase in the production of larger and heavier carcasses in the SA beef industry, it is essential to investigate the factors that might contribute to the increased occurrence of carcass conditions that might affect the supply of beef of consistent quality to consumers. A total of 12 abattoirs, across most of the 9 provinces of SA, were visited. The pH and temperature readings (at 1 hour and 2 hours post mortem) were taken on a total of 180 carcasses (90 per day) over a period of 2 days per abattoir. The beef carcasses were from both grain fed and grass-fed cattle, with additional data collected being whether the abattoir makes use of electrical stimulation (ES) or not, the cold and warm carcass weight, the age, and the fat code and the use of beta-agonists. The temperature at pH6 was measured to check for the proportion of carcasses with high rigor mortis temperature conditions. The frequency of occurrence of high rigor temperature carcasses across the 12 abattoirs was 65.64 %, with most of these carcasses falling under the weight category of 200-300 kg (40.09%). Carcass weight had an effect on the occurrence of rigor at a high temperature (p< 0.001) with an increase in carcass weight leading to an increase in the occurrence. The carcasses that went into rigor mortis at a high temperature, had an average weight of 283kg, while those at risk of going into rigor at high temperature had an average weight of 251kg. The group that did not go into rigor at high mortis temperature, had an average weight of 242kg. In general, it can therefore be said that carcasses that have a weight of over 250kg, are likely to go into rigor mortis at high temperatures. There was a significant effect of age and fat code on the incidence of high rigor (p<0.001 for both). The incidence of occurrence of high rigor temperature increased with an increase in fat code and increase in age. It must be noted however that the majority of the carcasses were fat code 2 and A age carcasses (the data was therefore skewed), which is what the majority of the SA abattoirs produce in terms of their carcasses. The use of beta-agonists (leading to an increase in carcass weight) and the use of ES on heavier carcasses, contribute towards the occurrence of high rigor temperature. Most abattoirs if not all in SA, make use of ES, hence it will be a requirement to manage the duration and timing of the ES correctly. The chiller rooms will also need to be re-adjusted and updated to accommodate the heavier carcasses produced in today’s market so that adequate chilling of the carcasses occurs.