Our facility holds GFCO certification, and we have our copacker facilities listed on our audit certificate as well. We are visited once per year for an internal audit (we still had our in-person audit even with the pandemic) and it's one of the easiest audits I have done if you are already a gluten-free facility. It was mostly a desk audit that looked at our HACCP plan, and they made sure we had things like an allergen program in place. They are really just checking that programs are in place. However, we are a meat manufacturing company, so we are relatively low risk for gluten contamination. The audit also included a very brief tour, since we do not have any gluten on site. None of our co-packers have ever had an issue with GFCO certification. I provide them the GFCO contact I have, and they schedule the audit themselves, and provide me the results afterwards.
GFCO also assigns risk levels to ingredients, and requires additional testing depending on other risk factors, as well as the history of your company. I would highly recommend working with them. They are usually quick to answer questions, and are more than willing to help you determine appropriate testing schedules. They provide newsletters as well, and partner with some other organizations that support those with Celiac disease, or gluten intolerance.
