Fortress Technology has announced that two North American customers have collaborated to produce frozen products, including hash browns, fries and onion rings. As a supplier of frozen retail, wholesale and foodservice potato products with global distribution, automation and technology are strong features at the firm’s multiple potato processing plants. 

Alongside scales, shakers, vibrators, graders, baggers, open bag detectors, case packers, sortation conveyors, palletizers and wrappers, located towards the end of multiple processing lines are several dozen highly-sensitive stealth metal detectors. Each is supplied with Fortress customized reject conveyors. 

Metal detectors are equipped with the food safety specialist’s, Halo Automatic Testing, to perform 180 hourly quality control tests on multiple product SKUs. Fortress also designed a secure reject system. The engineering of added safeguards to quarantine metal-contaminated products prevents contaminated products from being reintroduced to the line.

Testing the performance of conveyor metal detectors manually is common. However, the challenge for an operation of this magnitude is conforming to multiple QC testing criteria set by suppliers and switching between multiple product SKUs. In this instance, the frozen products range from smaller consumer-sized bags weighing from 0.5 lbs. to restaurant-sized bulk-packaged bags of french fries exceeding 20 lbs. 

For this processor, customer QC testing standards stipulated that three metal samples—ferrous, non-ferrous and stainless steel—be tested in three different but very exact product positions as the bags of frozen potato products pass through the center of the metal detector aperture. However, performing up to 180 manual tests hourly across multiple high-speed processing lines and checking the performance of the reject system would be labor intensive, disruptive to production and damage the good product. Leading to potentially high product wastage and costly production losses due to downtime.

Rather than relying on QC technicians to perform, document and submit these repeatable inspection tests, Fortress presented a business case to adopt its Halo Automatic Testing solution. Twenty-five systems were shipped to the company’s processing plants in two phases over the last decade. 

The company states that Halo enables the frozen potato processor to program and conform to customers’ performance verification testing program, including independently testing three metals in the leading, trailing and middle of product bags every hour.

Mimicking the disturbance caused by a test contaminant calibrated to the precise size, metal type and speed that product bags pass through the metal detector aperture—up to 150ppm for this potato processor—results in substantial labor savings. It also improves the test quality and accuracy of tests, emphasizes Fortress regional sales manager Eric Garr.

Garr describes the Fortress automated testing process, “The metal detector pulls in data from the infeed photo sensor to determine when Halo must trigger and introduce the simulated test sample in the leading edge, trailing edge and middle of the bag.”  This is always programmed to be in the aperture's exact geometric center to challenge the metal detector's performance. A process that can be extremely challenging to perform manually.

The requirement to perform leading, middle and trailing edge performance verifications was requested by a fast food chain customer. “‘Product effect’ is the main rationale,” explains Garr. He clarifies that bulky frozen products weighing up to 20 lbs. could produce high levels of false rejects. This distorts the results and could lead to a potentially high volume of product waste. “By testing all three metals in three positions ensures the product is not masking the metal samples in any position and also confirms that the reject system is tracking correctly. This is especially important in frozen bulk products when the characteristics might change due to slight thawing during the inspection phase.”

Switching and adapting to different test routines is equally straightforward. “Fortress cleverly engineered Halo so that test routines can be programmed by each SKU to the conformance standards set by individual customers,” explains Garr.

This means that for customers whose standards require one pass of each metal sample every hour, the infeed sensor picks this up and communicates with Halo to perform the verification tests aligned to each product SKU. “Switching between performance verifications all happens on the fly with no impact on production,” exclaims Garr.

Each production line will only halt if the metal detector performance test or reject check fails. To assist with audit traceability, each metal detector automatically logs all the data from each test, which can be extracted by USB and reviewed using Contact Reporter software. They are providing a reliable machine performance and due diligence audit trail.

Fortress added several extra failsafe features to ensure quarantined rejected products are never reintroduced to the processing line. This includes equipping each reject bin with magnetic locks and issuing controlled security card access to authorized personnel only.

With any products rejected during the Halo test, the reject bin automatically unlocks, enabling personnel to move the bags back upstream to be re-inspected. However, to distinguish between a genuine contaminant rejection and a product isolated during the Halo performance verification test, the metal detector bin door automatically remains locked if a reject is already present. “This robust solution provides trained and authorized QA personnel only with access to remove the products in order to conduct further investigations for metal contaminations,” verifies Garr. These added safeguards help to prevent contaminated products from being reintroduced to the line.