COLLEGE STATION — The meat industry’s constant quest for tenderness could benefit with just a touch, says a Texas Agricultural Experiment Station scientist working with a promising automatic meat-grading technology.
The “touch” is elastography, a new form of ultrasonic measurement developed for the medical field. It could also have important implications for beef, pork and poultry producers, according to Dr. Rhonda Miller of Texas A&M University’s animal science department.
Elastography compares standard ultrasonic readings with ultrasonic readings taken when meat, or any other tissue, is very slightly compressed. As Miller puts it, “It’s very light compression — really, no more than just a touch.”
Miller, a meat science specialist, has been working for a number of years with the use of ultrasound to measure the amount of fat in meat and its relation to tenderness. The beef industry in particular has sought methods to replace human visual evaluation of carcasses because it can be inconsistent and relatively slow. Beef consumers also are demanding leaner products that still have the taste and texture that fat, especially the intramuscular fat known as marbling, gives to meat.
Ultrasonic waves have been considered because they are useful for identifying the presence of tissues that vary in composition from surrounding tissues. Ultrasonic signals bounce off various meat components — such as muscle, fat or connective tissue — at different rates.
However, standard ultrasound technology cannot detect differences in meat components because it is not sensitive enough. Compressing the meat slightly allows for obtaining a second image. By measuring differences between the first and second ultrasound pictures, tissue softness and hardness can be determined. A team of experiment station researchers hopes to find how to automatically determine meat grades and tenderness by using this method, Miller said.
The technology was developed by Jonathan Ophir of the radiology department at the University of Texas Health Science Center in Houston. Ophir invented the technique for such medical purposes as gauging the size of tumors — which generally are harder than surrounding tissues — or the extent of liver disease.
Ophir came up with a method by which different readings from non-compressed and compressed tissues could be mathematically related. The readings can be presented both numerically and as digitized images that reflect proportions of various tissues.
Shortly after developing the three-year-old technology, Ophir served on a review panel for the National Cattlemen’s Association, which was evaluating proposals for automated meat grading systems.
Miller, with fellow researcher Dr. Dale Whittaker and others, had submitted a paper on ultrasound grading. “Jonathan is very interested in having elastography used in any industry where it can be beneficial, so he called us,” Miller said.
Ophir is now one of four principal investigators on the elastographic meat grading project. The others are Whittaker, who is an associate professor of agricultural engineering at Texas A&M, and Dr. Dan Hale, a meat specialist in animal science with the Texas Agricultural Extension Service.
Miller said the team is still working on which of 14 different mathematical approaches to comparing structure within an elastography image works best in providing a clear picture of where meat is fatty and where it’s not, among other things. The team must examine a large number of variables, from levels of meat marbling to how tender the meat is, and from location of connective tissue or tissue injuries that affect meat quality.
Each mathematical approach works differently depending on the size of the area being analyzed ultrasonically. The researchers must correlate readings from each approach with the size of the area analyzed. They also compare their elastographic data with actual sensory-panel data from human evaluators of the same meat, as well as chemical and other evaluations of the meat.
Once they work out which approach or approaches provide the most useful and accurate readings, they hope to develop a prototype elastographic machine that can quickly analyze beef quality and tenderness. They envision a machine with arms that grasp and stabilize carcasses on a processing line. An ultrasonic transducer, attached to a plate that compresses the meat, would take readings from the carcass.
The 1 percent compression rate is so light and so fast that both compressed and non- compressed readings are taken in a fraction of a second, Miller said.
The prototype probably will not be able to handle the standard 400 carcasses per hour that move through a beef plant line, Miller said, but added, “The engineers assure us that will not be a problem later.”
The prototype should be finished and on-line by the end of 1994. Major funding for the project comes from the Texas Advanced Technology Program, a state-funded research program that attempts to join public and private research efforts with commercial potential. A private Texas company is also involved in the project.
The potential for elastography is enormous in the meats industry, including poultry and pork processors, Miller said.
One estimate for turkey processors alone is that a $300,000 elastographic machine could pay for itself in two to three weeks by helping it identify turkey carcasses with too little water retention, Miller said.
“The industry wants this technology now, so we’re trying to put it on a fast track,” said Miller. “At the same time, we have to critically analyze it from every angle, because nobody else is doing work we can compare this to.
“We don’t want to propose it as the answer to all of the beef industry’s problems, but we think it can be a real benefit.”
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