I agree, those audits are a waste of time but I disagree that production having responsibility for quality is a bad thing. I have never worked in a company where QA staff do metal detection checks for example.
I think there are two parts to this; resolve the recurrent issues and you will do the QAs out of a job as it will quickly become apparent how pointless these audits are (every 20 mins IMO isn't an audit anyway, it's monitoring!) So you need to decide what the QAs will do when you drop the frequency of these and I would argue there is a lot to do that they're not doing, e.g.:
Auditing processes, e.g. auditing foreign body control as a specific audit in a focussed way. To decide what these audits should be, I would work through brc or whatever standard you're using and pick out each part. Then decide (according to risk as this is good justification to BRC for your audit plan) how often each part of that standard should be audited then make an audit plan. Admittedly these won't be every 20 mins but a good audit done thoroughly can take a full day.
Closing out corrective actions. Well they're not making sure this is done now!
Other standard QA tasks if not in production remit, e.g. glass auditing, air sampling, swabbing, taste panels, trials etc.
Right, now let's move onto the issue. To me it seems that there is lack of closing the loop and from experience I bet some of the blame should also be with the QAs and not just production. Put it this way, if I was one of your QAs, you would not get the same issue every 20 minutes! Part of this might be that the QAs don't understand what a reasonable response is. For me, a corrective action should have an immediate "correction" ie put it right now, and then a preventive action, ie "what do I do to prevent anyone doing this again?" (and the anyone is important.) Note without a good investigation into why something happens, the preventive action is normally not particularly effective. So, if a member of production staff misses a metal detection check, I bet at the moment the production staff will "talk to the person involved and redo check" or something similar? Not good enough. Why was that check missed? Were they too busy? Do they not see the importance? What I'm getting to is there a training need? If so, that need may be for everyone not just that one operator who was "caught out". Also are people really being held to account for CCPs and important quality attributes? If people repeatedly get away with things for no good reason (if there isn't a good reason) then it sends a message to the team that "quality is not important".
So on action, change your non conformance process to demand an immediate corrective action, investigation and preventive action. Make sure it's used appropriately (not for petty issues) by training your team and getting their buy in. Get the production managers buy in by pointing out if they get to the root cause they will have fewer recurrences and then less hassle and workload from QA but make sure they are prepared to be tough with persistent (fully trained) offenders and have a plan in your back pocket for when you decide to cut back on these audits!
