We had a similar issue with our inspector a few years ago. We use a short bladed knife, with a rounded blunt tip. Even with that, we had to start cutting the box along the side and then open the top so that we were not cutting over the meat. We do a knife check at start and end of each shift and train employees to immediately notify someone if their blade or any part of the knife breaks. - Once the operator opens the box (or a few) then he/she must clean and sanitize gloves prior to handling the product inside.
Since then our suppliers changed and now the frozen goods arrive in boxes with fitted lids and a sort of plastic tie around the box. With these boxes we just have to cut the ties making sure to properly dispose of them and then pull the lid off of the boxes. This seems to make our inspector more at ease. However, he still seems to enjoy watching the process at times, especially if we have a newbie on the job.