Whitney,
On further investigation, I see there are already threads on this site that can be searched on the topic of validation and specifically metal detector validation.
I also found a QUOTE from a LinkedIn thread that I think offers a clear definition of validation in the context of your question: " In my opinion the terms verification and validation are being misused. Validation is the act of determining the "problem to be solved" and specifying the appropriate device (MD in this case) that is capable of detecting and resolving the problem. Detection and rejection are both part of the system and must both be effective for the overall system to be effective. Validation is "Knowing you built the right system" to resolve the issue of what kind of metal contamination must be removed from the process to achieve a safe product.
Verification addresses whether you are operating the chosen system correctly. Verification of a system that does not meet the requirements necessary to "solve the problem" is of no use since whether the system is working correctly or not will not resolve unsafe product. The lack of verification on a Validated system is in the same boat since, if you do not test the system to assure it is operating consistently in the same manner you cannot be confident that it is doing its job correctly."
You (your facility and HACCP team) determine the problem to be solved during hazard analysis and risk assessment. The metal detector you procure for your facility needs to be appropriate for your product and for the hazard/risks you identified. The questions a validaation study needs to address include but are not limited to:
Will my products identified with metal inclusion risk fit through the aperture with the proper manufactures' recommended clearance? Are the frequency and sensitivity optimally set to detect the identified risk material? Is the metal detector located away from sources of interference at the point of use? Are the test pieces of the required size and material to challenge the anticipated identified risk material?
With respect to your question about PRP review: Your GFSI benchmarked scheme requires a scheme-specific Annual Audit. This annual audit is in addition to (not instead of) all the other normal and customary internal auditing that you would and should perform even if you were not GFSI benchmarked scheme certified. You need to perform your GMP audits, your periodic food safety audits of the food safety systems management plan, HACCP plan review whenever a change to the system is triggered, review of food security, defense and fraud. A GFSI Annual Audit actually includes auditing all your other internal audits.
