You can take "special" food and drinks for infants and toddlers through security - can't find an age limit anywhere though.
It is probably best if you put it into the bottle you will give it to your child in, or a collection of smaller containers rather than the big-sized cartons you get from the supermarket.
You just have to tell the person at security what it's for and they will look at how much you have and how long you are travelling for.....contrary to popular belief they won't make you drink it, but may take it away for special screening (which consists of putting the bottle into a little box and pressing a button..no idea what it does!).
Not sure where you are going to, but here are the guidelines from the US TSA (probably one of the strictest): http://www.tsa.gov/traveling-formula...milk-and-juice