With third-party certifications, regulations and consumer demands, inspection systems are getting more important all the time.
Metal detectors remain the most widely used line of defense, and we've covered them extensively in the past – including as recently as May (see Improved Metal Detection Technologies Play a Role in New Food Safety Systems). But X-ray and vision inspection systems are coming on strong because of some unique capabilities unmatched by metal detectors.
Not only do X-ray systems detect the same metal contaminants that metal detectors do, they also catch glass, high-density plastics, bone and other contaminants. Some can even detect deformed products.
"Also, more and more processors are using foil and metalized packaging, and metal detectors don't work in that situation," says Todd Grube, product manager-inspection systems in the Lititz, Pa., office of Heat and Control Inc. (www.heatandcontrol.com). Of course, the same can be said for cans.
"X-ray inspection systems combine the highest protection levels of functionality and detection sensitivity with maximum system reliability and productive uptime," says Robert Rogers, senior advisor on food safety and regulation for Mettler Toledo Product Inspection Group (www.mt.com/pi), Tampa, Fla.
"However, there is more to effective inspection than simply installing effective equipment. Proper installation, limiting false rejects, proper testing and verification activities, documentation and control of non-conforming product must also be considered in developing a program," he says.
An Ishida IX-GA X-ray system can identify damaged and missing product, in addition to detecting foreign objects. Inset photos are (clockwise from the upper left): a cheese brick with an internal air pocket; a crack in a chocolate bar; and a package of dim sum, one of which is missing a half. (Click on the image to enlarge).
"Incorporating options such as secure reject bins, USB data collection, system condition monitoring and complete due diligence packages are essential to make total food safety possible," Rogers adds.
There are a couple of newer applications for X-ray systems. One is reading bulk flowing products, even before they're packaged, like gravity-flow metal detectors.
"Product can be inspected from an infeed conveyor as it slides down a chute," says Grube. "Software can divert into a reject lane the portion of the product where a problem is found. We just installed a system for dehydrated potato flakes and it's working great."
Another application, he says, is weight estimation. An X-ray can take an image and measure the overall dimensions, and from that compute the weight. If the product is over or under the desired weight, it can be kicked out. "With the right algorithm, for some applications we can get as accurate as half a gram," Grube says.
Reject removal of a different type happens on the product sorting systems of Key Technology, due to a combination of vision inspection and air jet removal systems.
Key long has used vision to inspect products flying down its belts at high speeds. Speedy imaging software detects pebbles, twigs, animal parts and even discolored or off-spec items among the largely agricultural items its machines process. As the peas or Brussels sprouts make a short hop from one conveyor to another, rejected items are blown into an underneath container.
Want proof that it's working correctly? New software – FM Alert – provides documentation, including timestamps, that the system is on duty.
An even newer option is Three-Way Sorting, which provides not one but two ejector points. One can be fine-tuned to catch foreign material and other optimized for off-grade products.
Both of the above are available as upgrades for existing Manta and Optyx systems, as well as on new systems.
Mislabeling not long ago seemed like just an annoyance, but it has become a serious issue invoking legal liability, especially if a dangerous ingredient or allergen is not called out or is unreadable.
"Soon, 19 new provisions under the Food Safety Modernization Act will begin impacting food processing industries, several of which will increase the demand for vision inspection solutions," says Henry Ostholthoff, global marketing manager of Mettler Toledo CI-Vision (www.mt.com/ci-vision), Aurora, Ill. "Under new regulations, an unreadable label or incorrect label will result in a mandatory product recall and potential due to a labeling error.
"Labeling is now considered a CCP (critical control point) by many regulatory bodies. By implementing a vision inspection solution, manufacturers can ensure accurate labeling of ingredients and support product tracking through the supply chain." He adds vision systems are easy to integrate into existing lines.