If and when it comes, TEOTWAWKI  will certainly mean a disruption in food production and distribution. You should have enough food stored for your family to last a year, and much longer if you can afford it. Keep in mind that: you will need extra to dispense as charity, to your “head-in-the sand” relatives, to neighbors, friends, fellow church members, and refugees. So store lots of extra wheat, rice, beans, and honey. They are cheap now, but may be very expensive later.
You can “do it yourself” for nearly everything required for home food storage except canned powdered dry milk. It is messy to re-pack yourself, and because of milk’s butterfat content it only stores well for long periods with commercial nitrogen packing.
As previously mentioned, I sharply disagree with the LDS  (Mormon) church on their religious doctrines, but I commend them for their food storage philosophy, practice, and infrastructure. Your local LDS ward probably has a cannery, and they will let non-LDS members use it on a “space available” basis. Members are usually on hand to train “newbies” how to operate the equipment.
Bulk wheat, rice, and beans are best stored in 5 or 6-gallon food grade plastic pails. Walton Seed in Montpelier, Idaho  has excellent prices and they have top quality products.
If you use your own pails, make sure that they are certified “food grade” (buckets made for paint are not.) And if you re-use food grade buckets, make certain that they were only used for non-smelly foods. (Re-using pickle pails for rice will give you pickle-flavored rice!)
Alan T. Hagan has written an excellent FAQ on food storage. It describes some excellent methods. See: http://athagan.members.atlantic.net/PFSFAQ/PFSFAQ-1.html 
Date mark all of your storage foods. Consistently use FIFO (First In, First Out”) rotation.
Buy replacement cooking oil and Crisco every two years. This will be your biggest “recurring loss” food storage expense. (Donate the old oil and Crisco that is nearing its expiration to your local food bank. If you have any vegetable oil that has gone rancid, it can be saved for use as biodiesel. See my previous posts on this subject.)
If you can adapt your diet, buy more stable oils such as peanut oil and coconut oil that have a longer shelf life. They re also more healthful than Crisco or liquid vegetable oils.
Canning lids and rings—buy plenty of extras for barter.
Salt—stock up in quantity, particularly if your retreat is more than 30 miles inland!
Sulphur for drying fruits.
Vinegar-Buy a couple of cases of one-gallon bottles.
Food storage (freezer and vacuum) bags.
Aluminum foil (Buy lots! 101 uses, including making improvised solar ovens.)
Dog Food. Note: One of my old high school buddies, Scott T. who is now an attorney once quipped “A real survivalist would eat his dog.” But seriously, if your dog(s) will be useful for providing security, then store two years of dog food. Make sure that the dog food has a low fat content (for better long term storage) and that you store it in vermin-proof containers. Galvanized trash cans work fine for this purpose. You can get away with storing much less dog food if you live in an area with profuse deer, bear or elk; or if you raise a lot of livestock. Rotate your dog food just like you do the rest of your storage food.
Date mark all perishable foods with a medium point Sharpie pen. If you have a lot of canned goods to mark, then a date stamp will work.
Rotate your foods consistently. Always place the newest cans at the back of the shelf. Keep a multi-year rotation calendar.
Long term storage multi-vitamins and other food supplements: You should plan to supplement with a good quality double encapsulated multi-vitamin, a good quality B-complex tablet, and a 500-milligram vitamin C tablet. See Vita Cost  for some of the least expensive vitamins and nutritional supplements available via the Internet. They should be consumed and replaced at least every three years. Store them in a cool, very dark place. (Light kills vitamins quickly!)
Natural laxatives. (Your diet may shift heavily toward meat, and this could cause problems. Plan ahead.) Bulk Metamucil is one option.
Most families should do their own wet-pack canning and dehydrating. We also buy commercially canned (nitrogen packed) foods, some freeze dried foods, and some MREs (retort packaged.) As I will describe, some methods are more appropriate than others for certain foods.
See Carla Emery’s Encyclopedia of Country Living (published by Sasquatch Books)–a MUST for every survivalist’s bookshelf. The basic guideline for edibility is 2 years for meats and other “high acid” foods, and 4 years for all others. (See Carla’s book for a complete chart.) Edible, yes, but keep in mind that the nutritional value won’t all be there in four years. So store as many vitamins as you can rotate without going past expiration dates. (Roughly three to four years worth, unless you have an ultra cold medical freezer–I’d love to find one of those, used. They cost $3,000+, new!)
Nitrogen Packing is good for roughly 8-to-10 years for most foods and much longer for whole grains. I do not recommend storing flour. It only keeps two or three years.
Whole wheat stores for 20+ years with 80% or more of its nutritional value. Buy whole grains and a hand wheat grinder.
I recommend buying commercially nitrogen-packed cans only for the items that don’t store well otherwise (e.g. dehydrated peas, powdered milk, peanut butter powder, and textured vegetable protein (TVP).
You are better off buying some items in bulk (honey, whole grains, beans, and rice) and canning or otherwise “containerizing” them yourself. Canned nitrogen-packing of these items is ridiculously expensive, and there is very little advantage in storage life. Pack bulk grains and legumes in 5 or 6-gallon plastic buckets by yourself, and you will save a lot of money! Note: Make sure that you use oxygen-absorbing packets available from Walton’s or the dry ice displacement method to kill all the bugs/larvae before you seal up each bucket. (Again, see Mr. Hagan’s Food Storage FAQ .)
Commercially canned “year’s supply type units are needlessly expensive. (Even the salt comes canned. Talk about overkill packaging!) In the instance of wheat, you are paying two to five times as much for the product because of the packaging. (My most wheat purchase was at just $11 per hundredweight! Of course, I had to re-pack it all in six-gallon buckets.)