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The Big Cheese

LOMA SYSTEMS® true variable frequency metal detection technology helps Alpine Slicing & Cheese Conversion, also known as ‘The Big Cheese,’ raise their level of quality control.

When Bill Stuart and a few fellow cheese aficionados in Monroe, Wisconsin ventured out to form their own cheese packaging business in 2005, the result was Alpine Slicing & Cheese Conversion. The company provides slicing, cutting and packaging services to cheese producers nationwide.

One crucial part of the slicing and dicing process is to make sure no metal ends up in the final cheese product. The team has since built more flexibility into their processes with true variable frequency metal detection, taking their quality control standards to new levels.

Alpine converts bulk cheese from different cheese plants into slices, chunks and shreds. The end result usually ranges from an 8-ounce chunk, wedge or package of slices to a 5-pound deli piece. The company converts all natural cheese products, including organic and kosher. To wrap the cheese, Alpine typically uses polyethylene-based structures on a wide range of packaging equipment, including vacuum, gas flushing and both horizontal and vertical form-fill seals.

Because Alpine was building a new operation from scratch, it was the perfect time to choose flexible equipment that would deliver the performance they were looking for. Historically, metal detectors
operated on a single frequency, calibrated solely to specific product characteristics. With the introduction of two- and three-frequency metal detectors, those capabilities expanded, but sometimes results still showed compromised statistics. But when the team found a true variable frequency metal detector, they knew it was just the thing to help the company raise its level of quality control.

“We run a combined total of 78 different products and sizes through our metal detector,” said Bill Stuart, Alpine’s Plant Manager. “Before variable frequency came along, you would have to set the metal detector at a compromise point that would work for all of your products across the board.”

Because Stuart’s team converts cheese from other vendors into consumer-sized pieces, the product goes through cheese cutters and slicers, so it is important to detect any metal in the shavings. “We use the metal detector at the end of the process line to ensure there is no metal found as a result of slicing or chunking,” he said.

“The true variable frequency metal detection technology gives operators a dramatic choice in the way they can use a metal detector,” said Don Hannes, Regional Sales Manager at LOMA SYSTEMS, a manufacturer of metal detection, checkweighing, x-ray inspection and data management systems located out of Carol Stream, Illinois.

The metal detector analyzes product effect (temperature, moisture, salt content, speed, packaging material, etc.), reviews a broad band of frequencies and offers the right one for the specific application within seconds. The automatic calibrate/learn process of the metal detector analyzes the product characteristics through multiple product passes. “Through the learn process, the metal detector uses a product’s signature and signal as the means to identify it and through this process, it can then differentiate between metal-free and metal-contaminated product,” Hannes said. “It also can differentiate unnoticed and unwanted product changes. Depending on the value of the product effect signal it analyzes, the metal detector will choose the frequency that is optimal for the product. At any frequency setting, when a new product is analyzed and the product effect signal is too high, the metal detector will automatically reduce the frequency setting to establish the sweet spot for optimal metal detection,” he continued.

“More and more companies won’t do business with you if you don’t have metal detectors,” Stuart said. “We need true variable frequency detectors because we deal with all different kinds, shapes, and sizes of cheese. In our business we’re not running one product all the time. We change to different products and the true variable frequency gives us flexibility to do that. If you run an 8-ounce cheddar piece through, the metal detector would calibrate to that product. But because it’s true variable frequency, you can also have it programmed for a 2-pound piece of mozzarella. A lot of times, metal detectors are set for one size and type, but the true variable frequency gives you the option to run multiple sizes and shapes.”

Most metal detectors are sold with a single, fixed factory setting that is manufacturer determined through their history and experience. Even with two or three frequency settings to address some product variations, the operator is still limited. But operators now have the additional facet of frequency choice at their disposal to program the metal detector for the product.

“The continuing challenge from the market is to obtain smaller metal detection with technology advances,” Hannes said. “Operators can now have 70 embedded frequency values All previous parameters for correct product set-up on the metal detector remain the same. The added parameter is the operator’s ability to have the metal detector choose the optimal operating frequency for the product, rather than a suitable, but perhaps not optimal, factory-chosen frequency.”

The new true variable frequency metal detector takes things to an even higher level by offering Stuart’s team increased sensitivity and improved stability. “The ability to detect small particles accurately has really improved with the new equipment,” Stuart said. “It’s one more tool to help us meet our HACCP requirements.”

Hazard analysis and critical control points (HACCP) are used in food manufacturing facilities to keep food as safe as possible. There are seven guiding principles to a sound HACCP program and each individual food manufacturer develops a specific HACCP program to suit their overall process. The manufacturer will determine the metal detection standards to employ for finished product or in-process product inspection.

The LOMA SYSTEMS IQ3 metal detector’s capabilities are a result of the latest in case and coil geometry, which deliver immunity from vibration, electrical interference and thermal shock. Instead of a rectangular shape, the case design has a rounded top with additional bends that increase the rigidity of the metal form. “Using an energized three-coil arrangement creates the electromagnetic field of inspection,” Hannes said. “The coil design is what allows a true variable frequency metal detector with 70 choices, instead of two or three.”

Operators usually want a metal detector to provide the smallest metal detection possible and to do it with zero false positives. Having so many variable frequencies enables increased stability, which means fewer false positives. A false positive is a reject signal that occurs when detectable metal is not present in the food item. It can occur when product characteristics change, such as when expected frozen product is not frozen, or the metal detector has not learned the new product being inspected. Hannes states, “The unfrozen product will exhibit a vastly different product signature and product effect signal that will exceed the detection threshold of the metal detector.”

Stuart said his team is more productive with the HMI capabilities the detector offers including the language-based interface with multiple choices and user ID options with varying levels of security access. A graphics-driven touch screen simplifies communication and operation issues in a culturally diverse workforce that speaks multiple primary languages. “The touch screen is operator friendly,” Stuart said. “Before it was more elaborate to set up, but now you can just enter in the program you need. We don’t need the frustration of a new piece of equipment not working. We’re grateful the installation of these machines was flawless,” Stuart concluded.