All the food originally packed in 1997, the year the first Vault-Co web site went up, has been rotated out of Firehold Alpha, Silo One and Firehold Bravo. I found upon inspecting it that 90% of the food packed in that year is still edible and may even retain some nutritional content. Rice, powdered milk and sugar appear to have indefinite shelf lives when packed correctly. I suspect the new frontier is in rolled oats, which are a superb survival staple. I am betting that rolled oats in mylar with oxygen absorbers will last twenty years if stored at the correct temperature.
This new stock will not even be inspected until after the year 2012 passes and it is likely it will not be rotated until 2017. I expect by that time World War III will have come and gone and these staples will provide food during a long period when little food of any kind is available topside. Even if the Permaculture Lab is not operational then, there will certainly always be some limited fresh produce available from sprouting tubs and small rootstock gardens no matter how much of the Hive is functioning.
There's probably enough food in the drums in the photo above that combined with some supplemental canned goods could support a family of four for about six months. The large drum in the middle of the photo has enough freeze-dried meals in it to last four people 30 days by itself with no more preparation than hot water.
I am having to eat some of my MRE stock because I don't trust it ten years out. Some of it has already gone a bit flat and funny tasting with time. MREs are overrated for more than a decade but freeze dried food can last much longer at cool temperatures and low humidity.