Earlier this year (April), pest control at AMS seemed to be on top of this problem for the first time ever. In mid August, I can confirm the mice are back with a vengeance (at least in the Globalground and Menzies lounges). I asked the Globalground lounge dragon about food hygiene and she explained that they are extra careful to ensure that all cups and glasses are properly washed before they are put in the drinks/snacks area.