Love the Nature's Miracle stuff suggested. Leaves a nice smell. Worked great in the laundry on my son's grass stained soccer shorts too. Safe to use around pets and kids.

At 7 months what about just using a play yard with a quilt on the bottom that would be thick enough to absorb whatever was spit up but then could be tossed in the laundry and a clean one put down. At least it would confine the mess and keep it away from the other kids too.

I agree on the suggestion to get the doctor involved and to test the possibility of meds as a solution because this sounds beyond the norm.