I had to open baby milk once and taste it to satisfy airport security, not the most pleasant experience, wasn't resealable either
with regular milk i've always purchased in the airport, at heathrow in london, uk starbucks charged approx $5 for 4 pints and asked me to wait an hour before they agreed to give the milk, but at gatwick also london, uk i went to a milkshake place asking if i could buy milk to fill baby bottles and they filled them without charging, but i agree with full fat milk its not always easy to purchase it at the airport