How do you block food/drink spam?

Or at least filter it to another window?

If you mean what you see when others are drinking and eating then there is not really any way to block that.

But yes, you could create a secondary chat window solely for that and set your filter to put "Emotes" in that window, minimize it, and stuff it in the corner. But you might miss some important other emotes

Alternately if you cannot remove them then remove yourself from where they are eating/drinking which is probably the lobby

If you mean the ones you see when you run out of food then just eat and drink and fill your self up.