With a metal detector, metals that have one or both conductive magnetic characteristics — such as brass, bronze, ferrous metals, etc. — will create a detectable signal. Non-magnetic stainless steel is harder to pick up — it’s a bad conductor — and certain food products with added iron, moisture, salt and acids tend to mask metal detection. Known as the “product effect,” this can impact inspection performance.
However, technology has moved forward and detectors are now suited to wet and dry applications. Even conductive products consistently presented in small packaging will be picked up.