Next generation carcase measurement

Xbox cameras, medical technology and probes are the next frontier for the lamb supply chain.

MLA, through the Sheep CRC, is trialling new technologies to provide accurate real-time measurements of fat, meat and bone content, meat colour, intramuscular fat and eye muscle area in lamb carcases.

Most of these technologies will also have application in beef and goat processing.

Objectively measuring profitable carcase traits, such as lean meat yield and eating quality, could underpin value-based marketing and payment.

This represents a leap forward from the current practice of manually assessing carcases, such as palpating the grade rule (GR) measurement site (11cm from the midline at the 12th rib) in lambs, which can be inconsistent and inaccurate and provide only an estimate of carcase fatness. At the other end of the spectrum is CT scanning.

This provides an accurate measurement of fat, bone and muscle but the process is currently too slow for commercial chain speeds.

Murdoch University’s Associate Professor Graham Gardner said the next frontier was somewhere in between these options, and would involve commercially relevant tools that were cost effective and accurate.

“When it comes to meat measurement technology, we have two aims – measuring lean meat yield and measuring eating quality – that are important to the whole value chain (producers, processors, retailers) and to consumers,” Graham said.

“Both offer benefits back to producers through increased demand for product and the potential for premiums based on true carcase value.”

The quest to develop a range of tools to suit all processors – from hand-held rapid devices to automated systems – has seen researchers put technologies to the ‘real world test’ at processing plants across Australia.

One of the biggest challenges facing researchers has been how to accurately assess the whole carcase based on information from one measurement site, such as the GR site or the C site.

“The distribution of fat and muscle around the body of a lamb is influenced genetically, so a single-point measurement is biased,” Graham said.

“All this variability has a cost. From a lean meat yield perspective, it means more fat trimmed and inconsistent retail cut size, and in terms of eating quality it means lost consumer confidence. A whole-carcase measurement system would provide more accurate assessments.”

There are systems in place, such as the lamb MSA program, to predict traits like eating quality. Researchers have also developed a carcase value calculator that takes input values like GR tissue depth (measured accurately with a GR knife) and hot carcase weight to predict cut weight that, when multiplied by their value and summed, gives the carcase value.

“We have the pathway in place to act on variability in lean meat yield and eating quality, so all we need now are the measurement technologies to support these systems by accurately measuring traits such as intramuscular fat, eye muscle area and GR tissue depth; or – even better – true carcase composition,” Graham said.

A priority is to take measurements as early as possible – ideally on the hot carcase straight off the slaughter floor – so variability can be managed by sorting carcase-based lean meat yield and cuts based on size and eating quality.

As this requires hot carcase measurement devices, researchers face the challenge of converting some of the tools – which are optimised for cold cutting – so processors can make earlier product sorting decisions and more timely payments to producers.

However ‘cold’ grading technologies (i.e. just before the boning room) also offer value, given the greater flexibility of measurement options.

Resource Flock

Research and development for the sheep value chain needs sheep, and the ‘sheep behind the research’ are known as the Resource Flock.

With 150 new sires used each year, this flock provides a source of diverse genetic material, giving researchers a variety of animals to process. For example, across the whole flock the intramuscular fat in the loin varies from 2% to 9%, which is essential for testing the sensitivity of tools such as impedance probes.

This flock was formerly the Information Nucleus Flock (INF) under the first Sheep CRC. It was separated to become an industry asset – funded by MLA – to operate beyond the CRC. The Resource Flock is managed by the University of New England at Armidale and by the Department of Agriculture and Food Western Australia, at Katanning.

In the second half of 2015, 600 lambs from the Resource Flock were processed in 100-head lots to test prototype carcase measurement technologies such as Dual Emission X-ray Analysis (DEXA) as  part of the existing Scott Technology primal cutting system, 3D and hyper-spectral cameras, and near-infrared and electrical impedance probes.

After processing, the lambs were sent to Murdoch University, where the carcases were CT scanned and numerous muscle samples were collected to calibrate the other technologies.

“We compared the DEXA with the CT yield test, and it was the by far the most accurate technology so far,” Graham said.

“Using DEXA, we can explain 85% of the variation in carcase fatness. This compares to 15–30% using GR measurement and hot standard carcase weight, while visual scanning technology (VIAscan®) describes about 45%.”

Each carcase was then boned into commercial cuts – generating 163 different weights and measures per animal.

Researchers are using this data to calculate saleable meat yield and recalibrate the carcase calculator that will predict primal/cut and even muscle weights based on DEXA carcase composition and weight.

Graham said the next step will be to focus on creating industry-ready devices – ranging from automated technologies to hand-held devices to suit processors of all sizes – and paving the way for an MSA individual carcase system for sheep.

More Information

Dr Graham Gardner
E: g.gardner@murdoch.edu.au

Read about the evolution of processing technologies in the November/December 2015 edition of Feedback, due to reach mailboxes in mid-December.