There is both an issue with the key mapping (which can be addressed by davidor's method) and one or UrW's infuriating inventory reshuffling. The items to be examined via herb lore are usually at the end of the "food" list, but sometimes UrW reshuffles items on drop/pickup and sometimes not (with a lingering effect). Thus, when I pick up a bowl of stew from the cellar after having tanned a skin (and dropped everything held to pick them up afterwards), most of the time it ends up in the same location in the list, but sometimes it does not, in which case it's very easy to accidentally eat what's in the position where the stew should have been located.