No matter how soft they get. It isn't actually poisonous at this stage. If it spits the milk back out at you, it's no longer good. Milk is spoiled when it starts to look like yogurt. Yogurt is spoiled when it starts to look like cottage cheese.
Cottage cheese is spoiled when it starts to look like regular cheese.
Regular cheese is nothing but spoiled milk anyway and can't get any more spoiled than it is already. Most people think this is acceptable. When something starts pecking its way out of the shell, the egg is probably past its prime. Flour is spoiled when it wiggles, ot things fly out when you open it. Foods that have become an integral part of the defrosting problem in your freezer compartment will probably be spoiled by the time you pry them out with a kitchen knife.