Maybe he was Jewish ... Actually, under Talmudic Law (see: The Mishnah by Pinhas Kehati, page 31), there is a limit beyond which an exception is recognised in respect of certain prohibited foods: it is usually an amount 'less than the bulk of an olive'. I'm not sure whether that ruling applies in this case, though. I've seen lots of people buy a single tomato, onion or piece of fruit. If that's all one needs, why buy more? Perhaps the guy is on a strict one-rasher-a-day diet?