Instead of a "sell by" date, wouldn't it be more useful of grocery items sported a "use by" date? You could back into the "sell by" from the "use by" yourself -- "Ooh, the 'use by' is tomorrow, so unless I can use this in one day, I'd better not buy it" -- but who knows what the "use by" is from the "sell by"? Do you have a day to use the stuff after the "sell by" date? A week? A month? Who knows?