QMS Coordinator

I am in the process of helping my company get the BRC certification for their filter packaging. I need to find out what all I need to get up to speed on getting certified to be an internal auditor for this standard. I am already an Lead ISO 9001:2015 auditor, been auditing for the last 15 years. Not sure what I need to do for getting requirements to audit this standard for the company?

You will need to take an internal audit course for BRC as your starting point.  Food safety auditing is not the same as quality, and auditing from a quality perspective will probably miss some key items

Then you can perform a gap anaylsis on the process and then close the gaps and voila---ready for 3rd party certification

I also suggest you take some HACCP training to wrap your head around what the process should look like, then go through the FSMA rules that have been launched over the last couple of years