SNB’s Blog

It is crucial for food manufacturers to constantly monitor and scan products for metal contaminants. Constantly searching for metal contaminants allows manufacturers to comply with codes of practices and health and safety regulations. This blog will give a general overview of metal contamination in food products.

 

What Contaminants Can Be Found By A Metal Detector?

There are three main metallic contaminant groups. These being Ferrous, Non-Ferrous and Stainless Steel. Ferrous is an easily detected metal due to it being both conductive and magnetic. Non-ferrous is relatively easy to detect as it is usually a good conductor but is non-magnetic.

Of the three, Stainless Steel is the more so difficult containment to detect and trace as it is usually a poor conductor and is non-magnetic. Stainless Steel tends to come in a variety of different grades, with some being magnetic and others being non-magnetic. The conductivity of the various grades of Stainless Steel is generally low, these factors all contribute to the metallic contaminant being poor for detectability.

 

Can There Be Issues Finding Contaminants?

Manufacturers in the food, pharmaceutical and packaging industry tend to test their inspection equipment for the most common Stainless Steel grade, being 316. However, the detectability of these grade of contaminants can be hindered depending on the type of product. For example, if the product passing through an aperture is wet, it could contribute to a high product signal.

Another complication that your metal detector may face is detecting metallic pieces in certain orientations. For example, contaminants like thin slivers or screen wires due to orientation effect, it can give a smaller than the signals and may can go through undetected.

 

Can A Metal Detector Detect Other Contaminants?

Metal Detectors are only able to metal detect contaminants. If your production line is trying to detect contaminants such as glass, bone, stones or ceramics, then an X-Ray would be suited to the task.

 

What Are The Best Practices For Detecting Contaminants?

SNB recommends that customers test their metal detecting equipment hourly with the smallest possible test piece spheres achievable to detect. For example, 2.5mm Ferrous, 2.5mm Non-Ferrous and 3.0mm Stainless Steel. The test pieces should be placed as closely to the centre of the aperture as possible. The centre is weakest point of detection for a metal detector, hence testing at this specific point.

SNB Electronics also recommends that manufacturers record all hourly testing. This will convey whether there are any anomalies with the machine.

 

My Metal Detector Is Not Rejecting During Testing

If a metal detector on your production line is not rejecting contaminants properly, get in touch with SNB Electronics. We have service engineers based in Leeds West Yorkshire, Luton Bedfordshire and Bathgate West Lothian. SNB aims to attend customer sites on the same day that a breakdown call is made.

If you would like to get in touch regarding any of our products and services, call us on 01977 689555 or email on snb@metaldetector-rentals.co.uk