I'm working as a QA assistant and my company has been certified ISO 22000.
My company has just bought a metal detector (manual setting of the sensitivity) to check pre-packed salad vegetable and therefore we need to build up some documentation and record to update our system.
However, there are few things I need help:
1) how often we should check monitor the metal detector?
I got lots of information that it should be "at the start of the production, after a period of time (e.g. every 2 hours), change of product, at the end of the production". May I ask why we should check at the end of the production? Is it to ensure the whole metal detecting process is under controlled?
2) We have 4 types of pre-packed salad vegetable (150g/bag), the combinations are different but at the same weight. We have test the 4 products with test pieces (FE, CU and SUS), and we chose the lowest sensitivity among these 4 products to be out critical limit (e.g. FE 1.5mm; Non FE 2.5mm for Spinach, FE 1.8mm; Non FE 2.5mm for Rocket --> we made the CL as FE 1.8mm; Non FE 2.5mm for all 150g pre-packed salad vegetable). We make these 4 products into a "category", can we not need to check the metal detector when change the type of pre-packed salad vegetable, instead, we make it check when there is change in product category. Is it reasonable?
3) For the start up inspection of the metal detector, according to the information from different website, it seems that the test pieces should be pass the aperture along with the test pieces. However, my manager has raised a question of how we can make sure the product using for the start-up is really free from metalic contaminant and he suggested as we've done validation test on the the detectable sensitivity of each products so when we start up the metal detector we only have to check if the test piece is able to be detected by the aperture using our setting. And I'm confused as I think the the product attribute may affect the sensitivity (probably lower the sensitivity).
Could anyone can help me? Thank you!!!
(Sorry that my english is not very good and maybe not easy to understand, I will try my best to explain)