Product inspection systems

Increasing sensitivity demanded in metal detection

By Joseph James Whitworth

- Last updated on GMT

Fortress: 75% of audits that have a critical control point metal detector encounter a non-conformance issue
Fortress: 75% of audits that have a critical control point metal detector encounter a non-conformance issue

Related tags Metal detection Audit

Supermarkets are behind the demand for increasing sensitivity when it comes to metal detection, according to Fortress.

The firm said it is being asked about increased sensitivities for difficult applications and customized systems for challenging production lines.

It described metal detection as still being considered as a magic box with only a basic misunderstanding of how it works because people can’t see what is going on inside.

Supermarket demand

Steve Gidman, Fortress Technology president, told that the demand coming from supermarkets is a new thing.

“Walmart and Kroger have a lot of power and we are not used to these demands on performance level to what we couldn’t achieve before but we have been forced to push the limits we were at historically to the next level​,” he said.

“Wet cold products such as milk, mask metal signals but people want the same sensitivity from a box of cereals which is dry and easy. Technology on some dairy and meats is close to the performance levels to box of cereals.”

Gidman said that bottled product historically had not been big for metal detection but the supermarket pressure of “what if it ends up in the product” even if it hasn’t done before was seeing the sector grow.

“Applications in dairy and bottled drinks are a focus, though historically no-one has applied metal on these because of the theory it couldn’t get in there in the first place and there are the challenges to overcome such as metal closures which we are working on.”

Speed and space

Speed is a big issue with increasing output from food lines and less downtime, said Gidman.

“Plants with existing older lines want higher speed but there is no room on the production line so you need to be creative to achieve all the objectives. Lines run within inches so you can have four or five single detectors but no room or multi-lane with four lanes and one box at the end,” ​he said.

Steve Gidman Fortress
Steve Gidman, Fortress Technology president

“In existing or retrofitted plants there can be a space issue as metal detection is used a lot but some sites don’t have an allowance for the space needed for the machine.

“Having the machine higher up the line is a North American thing but it is catching on elsewhere because end of line is an expensive point. You don’t know what is going on further up the line.

“If you have one at the start when your ingredients come into the factory, you know which machine up the line the metal has come from.”

Fortress said it was being asked how to prepare for an audit or deal with a non-conformance, with 75% of audits that have a critical control point (CCP) metal detector encountering a non-conformance issue.

Speed of support is vital as the line is not run without the detector working and all products will be recalled from the last time it worked.

“We have worked on training auditors as the issue rate is fairly high, you hear some astounding stories so we tried to produce easier access to training videos.

“People need to know as much as auditors, this is what you need to plan for to play the game because the rules have changed.”

Varying issues

He said the issues vary across the board with big companies who don’t do well and small firms that are ahead of game.

“Failures include test samples not being certified, so there is no traceability and the auditor says ‘this could be home-made we don’t know what is in that’.

Gidman said it was hard to tell the future direction of the market but short term there would be a higher push toward performance in all applications to maximise detection. 

Related topics Food Safety & Quality

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