Five New Technologies for Inspection

Lab testing will always be the gold standard in food inspection, but rising throughput rates are leading to more quality assurance at the point of production.

By Kevin T. Higgins, Managing Editor

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The chute was an instant hit in California nut harvesting, Kadinger says. Shells, stones and other debris can account for as much as a quarter of walnuts fed into the system, and the chute achieves about a 98 percent efficiency rate in removing the debris. By combining the chute with Key's own three-way sorter, Kadinger predicts efficiencies will approach 100 percent, and value will be added. Whole nuts will be separated from pieces, then multiple data points will segregate the lightest colored, most valuable nuts in a single pass.

Hyperspectral's inspection potential goes beyond walnuts, however. The technology and supporting algorithms develop a biological fingerprint of the food being sorted. Defects that are undetectable with cameras are exposed. For example, a potato reacts to stress by withdrawing sugars from its extremities, resulting in dark splotches called sugar-ends in French fries and zebra chips in potato chips. If those defective fries and chips are removed upstream before value is added, yield and productivity are increased. Extensive testing has demonstrated the technology is effective. The challenge now is making it affordable.

“It’s driven by the market and whether the cost can be justified,” says Kadinger. “We believe it is a valuable improvement.”

Dual energy X-ray absorptiometry (DEXA) is an innovation that is further along the commercialization curve. DEXA uses two arrays of response diodes operating at two voltages to generate two 2D images of the product being inspected. When applied to beef trim, DEXA not only screens for bone and other contaminants, it calculates chemical lean content within 1 percent.

Conventional inspection relies on human judgment, “which is maybe within 5 percent, plus or minus,” notes Richard Hebel, product manager-FA at Eagle Product Inspection, Tampa, Fla., which is now a part of Mettler Toledo. “Trim can constitute up to 40 percent of the cow, so the market potential for DEXA is huge.”

DEXA units are being used in Australia, Latin America, the U.S. and Europe, “and we just installed our first unit in China,” he adds. Most domestic trim suppliers still rely on visual lean, but grinders are levying fines on suppliers who deliver out-of-spec trim, and that will drive greater adoption of DEXA, Hebel predicts.

The upside of IEDs

U.S. military superiority quickly overwhelmed local forces in Afghanistan and Iraq, but snuffing out guerilla resistance on both fronts proved much more difficult. Improvised explosive devices using trace amounts of metal caused many U.S. casualties. Better metal detectors were necessary to protect the troops, and that drove technical advancements that now are incorporated into the detectors used in food inspections.

Multi-frequency detectors exemplify this, measuring the strength and direction of multiple magnetic fields before focusing on one. The Italian firm CEIA has taken this one step farther with multi-spectrum technology that simultaneously and continuously monitors multiple frequencies. This advanced system detects both magnetic and non-magnetic metals, including stainless steel. An industrial version was introduced in 2009, and Hayward, Calif.-based Heat and Control Inc. began sales and support efforts for CEIA's unit in North America the following year.

Products with high salt or moisture content, such as cheese, frozen foods and nonhomogenous products, are a challenge for single- and multi-frequency detectors because the controls must mask the signal generated by the product being inspected, explains Todd Grube, Heat and Control's inspection product manager. With a multi-spectrum system, not only does the unit do "a much better job of masking" the product signal, it is able to generate qualitative data.

For example, temperature changes in product on a frozen line can be monitored over time; if the temperature drifts upward, the strength of the product signals will change. "If the data were tied to a plant network, it's not unrealistic to poll the detector and alert personnel before product quality is affected," says Grube.

Subpart E of the good manufacturing practices section of the Code of Federal Regulations governing food production specifies that processors "protect against the inclusion of metal or other extraneous material in food." That helps explain the presence of metal detectors in most production facilities. But when inspection tools can perform multiple functions to ensure product quality, the demands of high-volume throughput also are served, and value is added.

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