We perform pre-operational ATP swabs on our equipment. Currently we have a pass/ fail, with 50 being our limit and any results of 50+ must be re-cleaned with a passing re-swab prior to use. Our sanitation on our equipment is performed nightly, and they are allowed to dry overnight before swabs are performed. If they fail prior to production, they must be cleaned, swabbed, sanitized and then dried as our product is all dry mixture. It's quite a process, and can get tedious.
We are currently in the process of trending our results for this quarter and I need some opinions. We previously swabbed 4 separate spots on our mixers/ hoppers, and the process was slowing production and often yielding some strange results- fail a spot for example, re-clean and fail with a larger number. We moved to composite swabs because whenever they would come back with a failing swab, they would only re-clean the one are on the mixer that failed- ie one corner. However, while that was our standard process for years (prior to myself filling the position), I actually don't think it was a best practice as to me if one corner failed, they all are likely bad and need re-cleaned. So now we have one swab for all parts of the equipment, so that when the swab fails the whole piece of equipment is re-cleaned, which to me is the safest method- and will yield the most accurate results.
My issue comes with the fact that if we only swab each piece of equipment once weekly, and there are 12 swabs in a quarter, one failure could have us at a low passing percentage >90 for example. No equipment will pass 100% of the time, especially with human error always being a factor. So, how do I handle this when trending my results. What does everyone else do, I can't increase the cleans, as that would have us ATP swabbing each piece daily, and we'd likely never get to producing, and I can't imagine that any company does that.
Can anyone share any opinions on an acceptable pass/fail percentage for equipment cleaning? We trend each specific piece individually, so each mixer, hopper etc.