Here's the TSA's official word on this:
http://www.tsa.gov/travelers/airtrav...ren/index.shtm
Medications, baby formula and food, breast milk, and juice are allowed in reasonable quantities exceeding three ounces and are not required to be in the zip-top bag. Declare these items for inspection at the checkpoint
My own experience has been uneven (I know, it's hard to imagine, isn't it?).
While bottles with milk/formula have always been allowed, I've had TSA people refuse to allow juice boxes. I've even had one TSA person refuse to allow me to bring a bottle filled with water. Basically, if I mixed the formular and water before security, it was fine ... but I coudn't bring it through pre-mixed. I asked him if that made any sense to him ... he just shrugged.
So I think there's a big YMMV on all the advice you may get. But I'd bring a print-out of the TSA Web site quote above ... at least you'd have some info with you that might change their minds.