Ah yeah I gotcha. I thought the piping were just tubing conduits, now I realize they’re an actual return line.I don't worry about the food in the tubing, as it is all in the fridge up until it is fed into the main return plumbing (this is my main reason for having DOS pumps in the fridge).
Once it is in the return pump plumbing it, the food is in the display in ~10 seconds.
I'm not sure if I'm understanding this question, but the tubing from the DOS connects to my return pump plumbing using one of these bad boys
I used wadded up paper towels to clog the hole for weeks until I saw it work consistently well and then I used some of that insulation-in-a-spraycan to truly seal it.