The shelf life of electrically stimulated and CO2 aged lamb meat

Summary

This project consisted of four experiments to investigate the effects of recent processing improvements on lamb meat colour stability. 
Experiment 1 
The effect of vitamin E, supplied through supplements or green pasture, on colour stability of lamb meat that has not been electrically stimulated 
Experiment 2 
The effects of medium voltage electrical stimulation, ageing and vitamin E supplementation on the colour stability of lamb meat  
Experiment 3 
Consumer benchmarks for colour stability 
Experiment 4 
Comparison of different Hunterlab spectrophotometers for the purpose of measuring meat colour stability 

At the completion of the experimental work, recommendations were synthesised from data obtained from the different experiments into a summary document for the purpose of consultation with industry members (Commercialising Lamb Meat Colour Appendix 2).  Packaging meat as primal cuts in carbon dioxide for 10 days produced a highly acceptable colour and colour stability for lamb meat.   Medium voltage electrical stimulation caused no detrimental effects on retail display time under the current 48h shelf life scenario.  
​Results indicated that lamb meat should not be aged for longer than 10 days unless the vitamin E status of the lambs prior to slaughter can be assured. Extended ageing to 30 days is likely to reduce colour stability to an unacceptable level when the vitamin E concentration in meat is low.  Supplementation of the lamb finishing diet with vitamin E can improve the colour stability of lamb meat. For lambs backgrounded on dry pasture, the recommended rate of inclusion of vitamin E in a feedlot diet is 250ppm. This should be fed for a minimum period of 2 weeks prior to slaughter. To ensure that meat is attractive to consumers, the oxy/met ratio of lamb meat should not fall below 3.5 during the retail display period. Display period could be extended from 48h to 60h but would involve consideration of cut, lamb history, and ageing time.