MDPiney: if you put it in a collender to drain just befor vacuming it helps,also you can take a paper towel and fold it several times and place it in the bag after the meet it will catch any liquid befor it gets to the channel.that works great.
with things like berries that will mash,we put them in the freezerfor a few hrs. then vac.

you can even vac. stews; graveys and things like that if you put into a container the size of you bags and freeze,then take out and vac right then.