Shrinking the Haystack
In the meat- and poultry-processing industries, keeping consumers safe and product quality high is of utmost importance, and detection of foreign materials has risen through the ranks as a top priority for processors.
In fact, detection technology in the past few years alone has been a fast-developing innovation, and it continues to evolve as the industry demands further improvement. However, challenges remain, and researchers, designers and equipment suppliers are pushing hard to continue to improve the technology to aid processors.
Metal detection and X-ray technology are very sound technologies that have helped processors such as Johnsonville Sausage ensure and maintain product quality, says Brian Jacoby, senior project engineer at Johnsonville. However, lower-density items, such as wood, plastic and rubber, still cause concern for many processors.
“Some equipment manufacturers are making equipment with metal-detectable gaskets and O-rings and those types of things, which has helped,” he explains. “Some use a metal powder-like substance that they put in; some actually use a very fine metal shaving. They each have different abilities to be detected, but your lower-density materials are where the technology falls short from a detection standpoint.”
Jacoby believes this is a good start to solving the problem, but says that the industry cannot focus on one aspect for the ultimate solution.
“It’s good to go after those low-density materials, [but] there are going to have to be some new technologies developed down the road,” he says.
John Stewart, senior research engineer at the Georgia Tech Research Institute (GTRI), agrees with the promise of modifying the lower-density materials in some cases, but he cites the fact that they are more expensive and not always most effective.
“Sometimes,” Stewart says, “only relatively large pieces will cause detection.”
One technology Jacoby believes is the “next-generation” for foreign-material detection is ultrasound â€” a technology that is probably three to five years away from being fully developed to assist the industry. Stewart highlights some of the early applications of ultrasound technology, cautioning that it must be implemented properly.
“Holographic ultrasound can be used to identify plastic and soft bones for product streams inside a pipe,” he explains. “This technology might be used in conjunction with X-ray to help find soft products.”
Processors also can incorporate vision systems into their detection of lower-density materials as well, with some other procedural modifications.
“A vision system can be integrated into metal-detector stations to detect plastic particles on the surface of foods,” Stewart says. “Although this technique is not foolproof, it can detect a single piece of plastic from a larger article that has been chopped or grinded to small pieces. It can also be used to verify metal detector tests.
“Plastic liners and materials can be manufactured with food-safe fluorescent materials that offer high contrast with poultry, beef and pork,” he adds.
Allen Merritt, managing director of Allen & Associates Consulting Inc. and partner in the Sustainability Engineering Alliance, believes that application of dual or triple systems (X-ray, laser detection for determining width of product, and optical detection) will become more of the norm in the short term. Merritt, who is also the former vice president of science & technology for Gold Kist Inc., offers blue protective gloves often used by line workers for personal protection as a prime example.
“This rubber is very similar in density to meat and not a good candidate for X-ray detection,” he says. “Vision systems, on the other hand, can easily detect the color blue. Depending on what product is being processed, the challenge may shift from one of detection to one of ease of rejection of the contaminated product.”
Under these dual and triple systems, each technology would have its duty, working in tandem to reject product contaminated by a variety of materials.
A combination of these technologies would cover the spectrum of foreign particles that could make their way into the product stream. Still, none of these technologies has perfected the detection of soft bone particles, particularly in poultry-processing applications. Stewart advises processors inspect the remaining skeleton after the deboning process has been completed to ensure all of the bones remain. GTRI has developed a vision system that uses this concept for poultry frame inspection, and Stewart says the technology can serve a dual purpose.
“The system has the potential to provide real-time performance on debone yield as well as missing-bone detection,” he says.Wood chips are another potential contaminant for which processors demand a solution. Currently, Jacoby says Johnsonville’s solution for this issue is procedural, rather than technology-based.
“Product coming in on a semi-trailer is typically on a wood pallet, and we have dump stations where we take that product and use a combo dumper that grabs the wood pallet and pulls it back out of the dump zone,” he explains. “The product is then transferred right away into stainless-steel vats or plastic combos. You eliminate that combo bag and that wood right when it comes in the door.”
On the technology side, Merritt adds, processors and suppliers need to continue to work together with researchers to push detection improvement faster. Still, processors need to be aware that improvement of product safety and quality comes with a small price to pay, at least in the short term.
“Newer machines have added more computer-processing to address these problems,” he says. “Since speed of detection is limited by the time the computer needs to process data before moving to the next item, additional processing may reduce line speed but improve detection.”