I'm of the use your survival gear regularly and replace it school of thought. I don't currently have a car, but I keep a couple of Clifbars in my school bag and eat about one a week when I get peckish during class or wandering around town. I keep more in my room, so every time I eat one I just grab another and replace it.

When I had a car, I did something similar. I had a bag with about two days of packaged food that I enjoyed eating, and I just used it up when I felt like eating it. I'd never eat all of it at once, and I figured the day or so I had less than two days food between when I ate something and when I replaced it wasn't a big risk.

I did a lot of research on military rations from around the world and adapted things from all over especially the American First Strike Ration (http://nsrdec.natick.army.mil/media/fact/food/fsr.htm) and the British 12 hour ration (http://www.guardian.co.uk/uk/2011/feb/14/british-army-new-menu) both of which are heavily reliant on commercial snack food. Then I hunted around a lot and found some good packaged single serving foods. Everything I carried was straight from the grocery store, nothing exotic or hard to find so it was easy to replace. I also packaged things in quart and gallon ziplock bags to make one day rations. If I opened a ration, I replaced the whole thing. I used the same kind of rations for day hikes and replaced them then too. I don't remember the exact mix and quantities, here are some of the things I carried:

Clifbars/granola bars
Single serving pouches of nuts
Retort pouches of applesauce
Pouches of sardines/pouches of tuna
Peanut butter or almond butter
Pop tarts
Jerky
Candy, usually peanut M&Ms
Dry fruit/fruit leather
Pouches of olives

MRE=s in a trunk isn't the best ides during the warmer months if you check the shelf life charts on them. I rather like Mainstay, but then I also like Mre's. Millenium bars have fared well with the field testers fpr my site, which still under construction. I think I might get it up and sort of running sometime in the next fifty years. Not a computer savvy person. The milleniums are advertised with a five year life and store under extreme conditions. Also there are survival tabs. And jerky. The real, homemade jerky, not the greasy commercial stuff. Dried fruit, granola bars, etc. Hop this helps.

I found these in the local Walmart yesterday and my sweet tooth started humming:

http://www.heinz.co.uk/ourfood/pasta/tas...ed-dick-pudding

Canned goods are heavy but you don't have the same weight concerns in your trunk as you do on foot. I also like that canned goods are crush resistant. That can come in handy in the trunk.

Freezing is an issue here though, so I don't keep canned goods in the vehicles regularly. I take them for roadtrips but usually keep a box of cliff bars and peanut m&Ms in my trunk kit, because they're more versatile.

Added some new stuff:

Oatmeal

Pure Maple Syrup Crystals (Just found it in Trader Joes. I use maple syrup as my primary sweetener in coffee, tea, and oatmeal so this is perfect.)

Can of tuna

Hot Chocolate

3 in 1 instant coffee packets (Trader Joes)

Thanks for the tip; maple syrup is a very good sweetener.

I picked up some Harvest Food works Maple Syrup Crystals last week. They were well received in our taste test. (I didn't tell them I substituted during Sunday morning breakfast and nobody seemed to notice.) I've been wanting to find a light weight way to bring maple syrup to have with bannock and this will do the trick.

It's pretty easy to make - just add a half cup of boiling water to the crystals in the mixing bag. I'm going to try adding them straight into the bannock too.

MEC sells them for $4.25 and I found them at Sail for $3.99. I've learned not to count on Sail inventory so bought a couple of packs.

Harvest Foodworks Maple Syrup Crystals

I keep hearing that, but I have to say, I've eaten 15 year old MRE's that were stored in the garage when I lived in So Cal. Some weren't all that palatable (are they ever?) but no ill effects. I have a few in my car that are probably pushing the 5 year "shelf life."

I keep peanut butter packets, Tanka bars, Almonds, those nasty bright orange cheese crackers (a weird thing that I just happen to like) & hard candies. I do eat them regularly as well so they're not "long term." They're often my lunch or breakfast if I'm running late or just feeling hungry. Of course, then I replace them.

Definitely recommend the Tanka Bars, especially the spicy ones!

http://www.amazon.com/Justins-Natural-Cl...+butter+packets

http://www.tankabar.com/cgi-bin/nanf/public/main.cvw

Second the recommendation for Tanka bars. Unlike many of the packaged bar products, these pack a lot of protein, and I have a hankering for buffalo - real tasty stuff. Only drawback is that they are pricey, currently listing at $3 a bar. I just ordered a box from REI - in quantity I get a 20% discount. They do have a "best by" date,but i have consumed several that were years past their date,and they were excellent, still.

I am concerned about the heat in a trunk and its affect on lifespan of any food stored there, this relates to MREs since they are known to be heat affected.
Though I am unsure about everything ...most things are adversely affected by heat. Anyone know if freeze dried stuff is as sensitive as MREs ?
One answer would be to rotate it out frequently.... another would be maybe storing food in an insulated container like an empty ice chest ... that might slow things down, but eventually the heat will "soak in".

Aside from not storing lots of food ... and going with rotation and things like Mainstay bars ... I'm not sure what else to do.
-KW