sorry to be so slow in replying just picked up your question.Filtered milk is normal milk that's been through a filtering process to remove all chemicals and trace elements as well asremoving more bacteria than is normally removed from milk,hence the very long shelf life for unsterilised milk.When my husbnd was very ill a specialist advised us to always buy filtered milk and now on my own I can't stand the taste of unfiltered milk it's just such a clean taste what a sensible cat !. Hope it keeps as well as possible!!!!!!!