Metal Detection Procedure

Hello Everyone, I am working as a Food Safety and Quality Assurance Coordinator. I was looking at the Metal Detection Procedures today and I find the SOP on Metal Detection procedures a bit unclear. 

Currently, they are testing one metal type at a time to check the sensitivity. For example, for spinach, they only run it against the Ferrous strip.

From my understanding, the product should be tested against Ferrous, Non-Ferrous, and Stainless Steel. Could you please help me confirm the correct process?

Thank you for your guidance.

Yes, if it's a metal detector (not an x-ray) AND your packaging isn't metallic, then you should test Fe, Non Fe and SS.  But for foil packaging, some old applications have ferrous in foil metal detectors (so would only be testing Fe).  But it's a pretty old fashioned approach.  Most using packaging like that will have x-rays nowadays.

Apart from test piece choice there are also methods for testing metal detectors which have become a lot more onerous over my years in the food industry.  Let me know if you want more info on that.

You test what there is a reasonable level of risk of contamination for.  If they wrote a hazard analysis validation or other support for why they were only using one type of seed it might make sense.

By default most sites will test stainless steel, brass, and ferrous steel because those are the most likely materials to contaminate the product, because that is what the processing machinery is made of.