Haven't reviewed what is needed for the updated Certified Food Safety & Quality Auditor Certification, my experience is on the ASQ-Certified HACCP Auditor Certification.
I ended up doing 2 things which (for me) were very helpful.
1.) Download the body of knowledge and
2.) take the practice tests online.
I utilized the body of knowledge and the source references as my guide. Then spent 4 months (in off times from my employment) to study and pull any applicable information. The practice tests are very helpful in that you can dive a bit deeper into areas that you may not be as proficient at or need to work on. Also help prep for the course.
If going this route good luck as I will be working on the updated certification later this year. Would be great to hear some feedback on how this goes.