Unexplained CCP Deviations/Corrective Action

I am curious how you all deal with unexplained deviations, especially CCP's.  For example....... If you get a metal detector hit but you cannot explain the piece of "metal" that was found.  How do you explain a corrective action if you do not have an explanation as to what it even is?  All machinery is checked.  All maintenance employees are involved and search for the source.   

Thank you for any and all help.

So just to understand better, so your metal detector gave you an indication that your product contains metal but you don't think there was any metal?

No......... The metal detector detected a small piece of metal.  I have the piece.  But, we have searched everywhere and have no idea where it came from.  

So just to understand better, so your metal detector gave you an indication that your product contains metal but you don't think there was any metal?

Got it. What is the nature of your product? Perhaps it came in with the product/raw material? And was not really introduced into your process but rather from your supplier? Check the processes you do as well. Equipment, utensils, machinery really well, GMPs. sometimes it's not so obvious. 

As mentioned above I'd also significantly consider raw material, have your supplier investigate and show details of their controls, but keep the option open of contamination at your site

QA_123: 

IMO: Thorough root cause analysis should be performed, however, i agree there are some CCP's deviation that are unexplained. In these situations (like any other CCP deviation) it is important to record all possible investigation for the deviation and document it correctly. Your root cause conclusion should be " Undetermined" (or something similar), after all possible causes are checked and excluded, to close your CCP deviation.

Your corrective action should include monitoring of the same deviation on the same product/process for the next three processing runs/months/supplier raw products (it can vary per your interpretation). I agree this is not the best response, but if no cause is determined, the only option left is to monitor if any further issues are detected.

Like in the example your shared above:

You check all your equipment and no source is found. You check with your vendor and they have good control of all hazards (magnets /Metal detector ) and no deviation was recorded at their end. Therefore your root cause analysis stays Undetermined.

This is just my 2 cents, lets see what others have to say....

Totally agreed. If there is a tiny piece of metal (we go down to 1.2mm) how do you find where that came from??

If you've checked all the equipment, the metal detector is doing its job and we just say "continue to monitor". 

We sometimes fail to find any metal. It could be as small as magnetic dust (agricultural product) or it could be so deeply embedded in the product (only 6mm thick) we can't see it. And if it's not magnetic... then what? We just say "continue to monitor." If it keeps happening, we'll do more investigating. But as long as we have no reason to believe the metal detector is malfunctioning, it's doing its job and removing little bits of metal. Success!

2-year old thread. Thanks anyway. But yr procedure sounds incomplete.