Title text: I am firmly of the opinion that if something doesn't have a year on it, every time the expiration date rolls around it is good again for the two weeks preceding that date.
Most packaged food has an expiration date that indicates when the food will probably no longer be suitable for consumption. This could be due to any number of reasons; most products will rot or grow mold after their expiration date passes, but some processed foods will dry out or just generally become unpleasant long before they actually spoil. The expiration date is sometimes called a "best by" or "use by" date for this reason.
Some products don't list the year as part of the expiration date, on the assumption that by the time the year becomes an issue, the food will obviously be spoiled. Cueball is encountering this issue; clearly the yogurt has gone bad - it's raising "stink lines" and appears to have visible mold - but the expiration date only lists "May 12th" and it's currently May 7th, so the characters reason that it must still be good since the expiration date hasn't passed yet.
The Gregorian calendar was initially adopted in the Catholic European countries in 1582 to correct the slow drift of the seasons relative to the calendar year that occurred under the Julian calendar. The Protestant and Orthodox countries were slower to adopt it. The British Empire, including the American colonies, adopted the Gregorian calendar in 1752. Cueball sarcastically wonders whether the expiration date might have been printed under the Julian Calendar, i.e., several hundred years ago.
- The Julian calendar overestimated the length of a year by 10 minutes 48 seconds or about 1 day every 128 years. The Gregorian calendar has 97 leap days every 400 years instead of 100, which reduces the error to about 1 day in 3300 years.
- As each country adopted the Gregorian calendar, it was necessary to skip the appropriate number of days to realign the Vernal Equinox with March 21. When the British Empire adopted the Gregorian calendar in 1752, 11 days had to be skipped, so in the English-speaking countries, September 2, 1752 under the Julian calendar was immediately followed by September 14, 1752 under the Gregorian calendar; there was no September 3–13 in that year.
- [Cueball is holding a cup at arm's length. Waves of stink are rising from it.]
- Cueball: Oh God, how old is this yogurt in your fridge?
- [Someone speaks from off-panel.]
- Person: What's the expiration date?
- [Cueball holds up the cup to look at the bottom.]
- Cueball: May 12th, but there's no year.
- [From off-panel again.]
- Person: It's May 7th. So it's fine.
- [Now the second person is on panel, and Cueball speaks from off-panel. The second person is sitting down working on a laptop.]
- Cueball: I'm not sure. When it was packaged, was civilization using the Gregorian or Julian calendar?
- Person: Okay, I'll throw it out.
- Cueball: No, it might still be good!