By following several important management practices in the weeks before slaughter, goatmeat producers can significantly improve goatmeat eating quality. This was one of the key findings of electrically stimulated goatmeat experiments conducted by MLA. New technology developed by MLA with research and commercial partners has made it possible to produce premium tender quality goatmeat without the need for long, slow cooking methods. The technology, which has been adapted from current sheep and cattle processes, relies on applying dose-controlled electrical current to goat carcases during the abattoir process. Recent experiments revealed that the mid-voltage electrical stimulation system has the potential to provide comparable advantages to the goatmeat industry to those already identified for sheep and beef. The problem is however that most goats presented for slaughter have not been through a finishing system in the last few weeks prior to slaughter that allows the product to benefit from the application of the new technology.
Why research eating quality?
The application of technology to improve the eating quality of Australian goatmeat was identified as an important way to increase the supply of superior eating quality (tender) goatmeat to the export and domestic markets. Although Australian goatmeat is recognised around the world as being of exceptional quality and food safety, supported by world class industry systems such as LPA and the NVDs, the vast majority of this product is cooked using methods that neutralise eating quality variability or the potential toughness of the meat. That is to say that this meat is generally slow cooked for long periods in dishes similar to stew or curry.
With the emergence of a high value chilled domestic market and the application of western cooking methods to goatmeat, the need to guarantee the tenderness of goatmeat has become apparent. Goat carcasses generally experience fast rates of chilling due to their leanness (lack of fat cover) and light weights relative to sheep. Consequently these carcases are particularly susceptible to a condition called cold-shortening where the muscle fibres contract before rigor mortis has time to fully set in. This results in tough meat. Electrical stimulation technology has been developed as a suitable method for addressing this issue and minimising the effect of cold shortening however a critical ingredient in the effective application of the electrical stimulation technology is muscle glycogen. The level of muscle glycogen in most of the goats included in the research was found to be insufficient to allow the effective application of the technology.
Not only does low muscle glycogen reduce the response to stimulation and increase the likelihood of tough meat, but it also means the final pH of the meat is higher and this reduces the shelf-life of the meat when vacuum packed. Following this research, a series of three fact sheets have been produced by MLA to assist producers in delivering goats to slaughter in a way that will maximise eating quality potential and these are outlined below.
The effect of finishing on goatmeat eating quality - key points: For optimum eating quality results, goats should be in reasonable condition and gaining weight preslaughter. The optimal weight gain scenario has not been gauged for goats however in prime lambs, a weight gain of 100-150gm/day is recommended.The type of finishing system has little effect on eating quality, provided that goats are gaining weight before slaughter.Diets that result in weight loss in the weeks before slaughter cause meat quality problems.Stress prior to slaughter can reduce levels of muscle glycogen.Reduced glycogen will increase muscle pH and cause dark cutting meat.
Requirements for handling goats to maximise eating quality - key points: Total time off feed should not be greater than 48 hours (for on-farm curfew, transport and lairage) until slaughter.Minimise stress during curfew, transport and lairage.Unweaned kids are likely to be more susceptible to stress caused by handling than weaned kids.Minimise the time between mustering and slaughter.Allow a minimum of two weeks at consignment property before dispatch.Access to water should be available during on-farm curfew and lairage.
The effect of pH on goatmeat eating quality - key points: Glycogen levels prior to slaughter will determine the ultimate pH.Electrical stimulation can be used to ensure carcases enter rigor (pH 6) at the desired temperature.Tenderstretch carcases hung by the pelvis have a wider temperature window and can enter rigor between 8 degrees Celcius and 30 degrees Celcius, in combination with five days ageing.Aggressive chilling regimes (ie high air speed, low temperature) can increase toughness. This is particularly important for goats which typically have low levels of fat coverage and cool more quickly.
Outcomes of the project
At the time, commercial and financial benefits had not yet been quantified for suppliers of goat meat. A trial had been undertaken to electrically stimulate goat meat and it revealed comparable commercial advantages to the goat meat industry with regard to enhanced product tenderness to those already identified for the sheep meat industry. This project evaluated a range of meat electronics in one plant supplying goat meat to domestic markets, and optimal settings will be developed for a case study of one domestic chilled goat processing plant. Each of these publications can be downloaded from the MLA website.