Ganz einfach. Ney York hat seine eigenen Gesetze, die das Lebensmittelrcht betreffen. Die sind strenger als anders wo, deshalb dort ein früheres Ablaufdatum.

Quelle:

Yes and no. Thanks to a recent Ask Metafilter post, we found that the ever-reliable Florence Fabricant actually tackled this question in the New York Times way back in 1982. It turns out that NYC has its own rules and dairy dating systems, rules that require shops to stop selling fluid dairy products four days (96 hours) after 6:00 a.m. on the day they were pasteurized, instead of a more common 6-10 day window used in other places. Dairies that sell within the city as well as to other nearby locations double-mark their products–hence the baffling date stamps. The rationale behind the short sale span is simple: sometimes dairy products are left out on the sidewalk in front of stores or are left unrefrigerated in grocery delivery trucks for significant periods of time.

Read more: http://www.city-data.com/forum/new-york-city/241935-why-does-milk-have-earlier-expiration.html#ixzz0sA6aqGRe

das mit der Milch ist so: NYC bebt!!! -ältere milch würde zu schlagobers werden!!