Leviticus 14:47

And he that lieth in the house shall wash his clothes
Which is more than bare entrance into it, and might be supposed the more to be infected by it, and therefore obliged to the washing of himself, and his garments: and he that eateth in the house shall wash his clothes;
if he stayed no longer than while he ate half a piece of wheaten bread he was clean, but not if he stayed so long as to eat a like quantity of barley bread, and sat down and ate it with food ^F18.