Project number: 73504
Lead contractor: University of Bristol
Start & end date: July 2011 – March 2012
Actual end date: April 2012
Approximately 14% of sheep slaughtered for human consumption in the UK are cull ewes and rams. In addition there is a growing interest in finishing older sheep, that have not been used for breeding, specifically for mutton.
It is known that meat from older sheep is tougher than that from younger animals. This has been clearly demonstrated in old season’s lambs compared with new season’s lambs. Optimising post slaughter practices can markedly improve the eating quality (particularly tenderness) of old seasons lambs. It is likely that the same practices (such as hip suspension, electrical stimulation and maturation) would benefit meat from older sheep (over 2 years of age). This work is being undertaken in order to prepare guidelines for the sheep industry on post slaughter practises for mutton quality.
- To undertake a literature review of factors influencing quality of meat from older sheep.
- To test effects of post slaughter practices on quality of meat from older sheep.
The practical work was conducted through the University abattoir and the following treatments were compared:
- low voltage electric stimulation
- high voltage electrical stimulation
- hip suspension
Seven and fourteen days maturation were compared within main treatments.
The results show that post slaughter treatments can be effective in mutton carcases but not all treatments are as effective as in younger animals. In summary:
- HVES of a side produced meat that was more tender than the control side of the same animal.
- Hip suspension of a side alone had no effect on tenderness,
- LVES alone produced meat that was more tender than control animals from the same kill.
- Adding hip suspension to low voltage electrical stimulation did not improve tenderness further.
- Ageing meat to 14 days post-slaughter improved tenderness over 7 day aged meat whatever the other treatments.
- Ageing controls from 7 to 14 days produced meat as tender as the 7d HVES or LVES meat, but ageing combined with HVES produced more tender meat than its aged control equivalent.
Ageing mutton to 14 days post-slaughter produced more tender meat than that aged 7 days, but low or high voltage electrical stimulation will improve mutton tenderness over non-stimulated controls, particularly if only aged for 7 days before consumption. Aging for a further 7 days will confer extra advantage. Hip suspension does not appear to have any benefit for mutton loin muscle tenderisation.
These results will form the basis for advice on improving mutton quality for the meat industry.