i made tons of pancake batter last tuesday and have just found what was left at the back of the fridge. It was put in a sealed tupperware that day. Will it be ok?
if it hasn't got mould on it and doesn't smell hugely off then i'd give it a go. sour milk is used in baking, and i regularly use eggs which are a couple of weeks old so i doubt you'd come to any harm. i'd use it.