Instead of the chuck try ground skinless chicken breast or TVP (textured vegetable protein), a soy product that works fantastically as a replacement for ground beef. Meat is just a huge trigger for so many folks with IBS, it doesn't hurt to just avoid it completely. I'd use soy or rice milk to replace the dairy, too.
Do you serve this over rice or with bread? It seems almost a bit Russian in flavor - maybe potatoes would be great with it?
My husband adores sweet and sour cabbage, so I am definitely going to make this soup!