Ragi in its unmilled state is supposed to last a long time. I got a bag of the flour from an Indian grocery store, and I like the taste of it, so I also decided to try growing it this year. If I get a good crop, I'll have to test it and see how long it can last.
As to an imminent food crisis, there are several happening around the world: Syria, South Sudan, Darfur. There are other, political explanations of what the troubles there are, but believe me, if farmers were able to grow abundant crops, there would be no food crisis and hence no political crises. Ukraine is a political crisis, but not a food crisis, because Ukraine is a food exporter. Whatever the bickering between the Ukrainians and the Russians is about, it isn't about food and both sides are well fed.
To expect an imminent food crisis, you have to expect two things: (1) people run out of money and (2) people run out of things they can eat. The first prerequisite is pretty common, people run out of money all the time. In fact, it is a small percentage that have
enough money to buy all their immediate wants. But when people with no money also find themselves with nothing to harvest, glean, forage, hunt, trap, or fish, they get very surly very quick. Astute readers of history will point out that people will raid before they will starve.
With the amount of food that gets thrown out in the U.S., we are in no danger of an imminent food crisis. Up to 50% of food that leaves a field ends up in a landfill. That builds a lot of slack into the system here, and it would take us a long time to burn through all the fodder in the pipeline, even if the supply end of the pipeline were to quit being replenished tomorrow.
Of
course, the longest lasting food is the one that is still growing, the bush outside your front door that you can snip a little bit off of whenever you get hungry. That is what
permaculture and the idea of a food forest is about, isn't it? Being able to walk about your property every day with your foraging basket and being able to gather everything you need to satisfy your nutritional needs? I've almost got that figured out for my little patch of the Georgia pine woods. For the warm months of the year, I have taro growing, and for the cool months collards. Between those two, I can always have a pot of greens on the stove.