Pre-slaughter stress affects meat quality

WHILE breed, age and diet of animal are all widely accepted as factors affecting meat quality, pre-slaughter handling of the animal and post mortem handling of the carcase have a greater influence.

Dr Paul Warriss of the University of Bristol (pictured, right) told producers the main lean meat quality problems were caused by stress pre-slaughter, resulting in meat known as ‘dark, firm, dry’ (DFD) or ‘dark cutting beef’ (DCB) and bruising.

Any of these cause loss of carcase yield, and, therefore, a huge financial loss to the industry as a whole.

Dr Warriss said normal beef initially contained a lot of glycogen, which is converted into lactic acid post mortem. In DFD beef, the muscle glycogen has been depleted by long-term stress before slaughter. This ultimately results in the muscle having a higher pH, which affects the meat structure, leading to meat that is dark in colour and also deteriorates more quickly, shortening its shelf life.

While DFD beef may be tender, it does have an overall reduced eating quality.

Dr Warriss said the major cause of DFD is allowing unfamiliar animals to mix before slaughter. Animals from live auctions tended to have a higher rate of DFD than those coming direct from the farm.

He said other factors likely to increase DFD were cold weather, long transport times, length of time in lairage and feed withdrawal. It is conservatively estimated that DFD beef costs the meat industry £9 million per year and bruising a further £5 million.

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