When I read the subject line, the only thought that occurred to me was texture, not safety. I can't think of a reason why it wouldn't be safe and, since they're already stewed, the texture will suffer less (though my guess is they'll turn mushy). If you're truly concerned, check out the Department of Agriculture website; I think there's a Food Safety Administration or some such thing within it that has all kinds of useful information for questions like this.
Gypsy Boy
"I am not a glutton--I am an explorer of food." (Erma Bombeck)