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High Performance Metal Detectors Offer More Haste Less Food Waste

multi aperture multi lane metal detector

The most recent research shared by food waste prevention experts WRAP reveals that over half of the food waste generated by the UK manufacturing and retail sector is avoidable. Good news is, the figures appear to be falling.

Phil Brown, European Managing Director, Fortress Technology explains how faster high performance metal detector systems play a part in reducing the volume of false rejects and subsequently avoidable food waste.

Total food waste – avoidable and unavoidable – across the UK supply chain in 2015 was an estimated 1.7 million tonnes, with surplus and waste in manufacturing representing the equivalent of 4.2% of UK production (around 58 million tonnes). Retailers and manufacturers are already doing a lot to ensure suitable food surplus is being made available for redistribution, and under the UK Courtauld 2025 Commitment, three signatories reported a 74% increase in the amounts being redistributed between 2012 and 2014 reports WRAP.

Equipment choices, robust quality control processes and staff training are all critical factors when it comes to reducing factory food waste states Phil. However, putting all these waste reducing mechanisms in place doesn’t mean compromising on line speed.

“If anything, production lines today need to be faster, accommodate quicker product changeovers, recalibrate at the touch of a button and provide suppliers with assurance that contaminants haven’t slipped through the net,” says Phil.

The newest metal detection technology can help to keep waste to a minimum while maintaining high product integrity and food safety levels.

false rejects

False rejects occur when good product is identified as containing a metal contaminant and can cost a food manufacturer up to £14k annually per line.

Cutting false rejects

False rejections occur when perfectly good product is identified as containing a contaminant. The product has to be discarded, regardless of whether metal has actually entered the food chain or not. This is more common on lines inspecting wet products, such as dairy, ready meals, dips, meat, poultry and fish, bakery and even salted and fortified mineral snacks.

Primarily this is because food metal detectors have until recently struggled to reliably distinguish between the signal generated by a genuine metal contaminant and the signal caused by product effect. Moreover, stainless steel has been especially difficult to detect in wet products since any signal can be effectively disguised by the product effect.

Adding up the amount of product wasted due to false rejects can be challenging. Yet, industry estimates put the cost per line of false rejects at up to £14,000, depending on the scale of the problem. In addition to physical waste, repeated line stoppages to clear reject bins and troubleshoot machine issues can undermine the cost effectiveness on production lines.

Designed to overcome this issue, the Interceptor metal detector from Fortress applies both high and low frequency ranges in order to isolate the product signal, and more readily identifies any contaminant signature beyond that. Trials with stainless steel in wet products have shown that Interceptor can pinpoint contaminants half the size of those detectable by former generations of equipment.

surplus waste

Surplus and waste from UK manufacturing represents approx. 4.2% of overall UK food production

Increasing inspection output

Increasing the volume of inspection lanes for specific product ranges can also attain reduced food waste and enhance inspection productivity.

This could be accomplished by channelling multiple lanes through a single, large metal detection aperture. The clear drawback here is that the larger aperture size sacrifices valuable levels of sensitivity. In addition, any reject system will remove an entire line of product across all of the lanes being checked, so creating unnecessary waste.

Of course, there is the option of positioning a separate metal detector over each lane. This will mean product is only ever rejected from one lane, but the approach has major impacts in terms of cost and space efficiency. In today’s food factories, many of them working around legacy equipment and within severe spatial limitations, compact design is often a prime consideration.

Because the multi-aperture multi-lane metal detector designed by Fortress has a dedicated aperture for each lane, the system is more sensitive to smaller metal particles and copes better with orientation and product effect. Best of all, each aperture operates like a standalone metal detector, inspecting and rejecting products on each line. So, in a twin lane configuration, false reject waste can instantly be halved.

A single control panel manages all lanes, which streamlines operator access and enables users to select and view production data by individual lane as well as analyse comparative lane data side-by-side. Because each lane can be programmed to run asynchronously from each other, if one lane goes down or requires maintenance, the remaining continue to run as normal. Which means production never has to grind to a halt.

“Our recent developments in metal detection can have a direct bearing on the amount of food waste manufacturers generate. It serves to demonstrate that food safety on the one hand and concerns about cost, speed and wastage naturally overlap. What’s more it proves that on fast moving production lines haste doesn’t always equate to more waste,” add Phil.


1 www.wrap.org.uk/content/how-grocery-supply-chain-can-save-£millions-tackling-food-waste

Fortress Technology (Europe) Ltd

We are a leading designer and manufacturer of ‘Phantom’ & “Stealth” branded metal detection systems for a wide range of markets to satisfy both customer and retailer codes of practice, including BRC.

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