Dear Meraj.udct,
Actually, HACCP can be varied from one factory to another factory if the process flow and conditions are different. You need to perform your own risk analysis.
Gather your technical team from multiple department such as production, quality, maintenance, purchase, etc. Brain storm for hazards that might be involve in each step (some can be referred from scientific data; some can be from history record such as customer complaint, non-conformance production issue; some can be from backgroup or experience of your team or other similar facilities). Don't forget the risk from the equipment, control system, working environment, and your facility working culture. Then make decision using decision tree to determine for CCP.
Metal detector is recommended and if used, it normally considered as CCP. If no metal detector, you need to perform risk assessment why metal detector is not necessary. Documented your risk assessment.
So far, reasons of factories that did not install metal detector are
1) There are other methods to remove metal fragments and the size is smaller than test pieces that use for metal detector. As DP2006 suggested, you can use sieve and inspect sieve condition. Consider sieving as CCP instead. Another idea is "magnet"....however, you need to check magnet efficiency and inspect the magnet as well.
2) Packaging material is metal (e.g. metal cans, foil, etc.)....so metal detector might not be able to install. However, this might be weak due to there is in-process metal detector available, so metal detector can be used before products are packed in that metal packaging materials.
3) Equipment control and no easily broken metal equipment involved. I think US-FDA considered any equipment with thickness (diameter) more than 7 mm as non-easily broken materials. With grinder machine, I don't think you can use this reason in your risk assessment if there is any blade in the grinder.
Hope this helps.
Regards,