How long do foods last without refrigeration?

This is a question that’s been tickling the back of my brain for quite a while. We tend to refrigerate just about everything in America because (a) energy is so cheap and (b) it’s easier than thinking about it. But what do you do if there’s an extended power outage – what gets thrown out, what is kept? What if you don’t get the energy system for your Peak Oil Homestead installed before Peak Oil hits and you have to live without a refrigerator?

First off, a refrigerator merely slows down biological processes (As opposed to a freezer which effectively stops most reactions at the usual cost of flavor, texture, and structure). Lower (or higher) temperatures affect spoilage rates, and some foods are more resistant to contamination than others.

According to Heinz, opened ketchup does not need refrigeration and will retain its flavor for upwards of a month. I found similar recommendations for mustard, BBQ sauce, and other condiments. Opened jams, jellies, pickles, olives, honey and so forth do not require refrigeration over the short-term. All of the above items will last for 1.5 – 5 years when stored unopened due to the seal keeping out mold spores and bacteria. Always check canned food for contamination by looking for dents, cracks, or bulging. If the seal appears broken in any way, carefully discard the food immediately.

Eggs may stay unrefrigerated for a time (fresh eggs longer than commercially-sold eggs). In a quote attributed to Alton Brown, he states that unrefrigerated eggs age roughly a week’s worth of refrigerated time in a day (depending on temperature, of course). Given that eggs typically last 6 – 8 weeks in a refrigerator, that gives you about a week to eat a fresh egg. A good check for egg freshness is to see if it floats – if it does, the inner air pocket has expanded and the egg should probably be discarded.

There are as many recommendations for storing cheese as there are types of cheese. The general consensus is that the best place to store cheese is in a cool (45 – 55°F) larder or cellar. Failing that, the warmest part of a refrigerator is acceptable. Hard cheeses (parmesan, romano, cheddar) may be stored at “room temperature” for significant periods of time if they are kept moist. One recommendation is to wrap the cheese in a vinegar-soaked cloth to prevent mold formation and retain moisture.

Butter and margarine have a longer unrefrigerated life than I had expected. Butter stores best when using a water seal (FYI: annoying video at this link), but can sit for several days unrefrigerated on the counter.

In general, I have a few thoughts with regard to storing food after studying much of the research. The acidity of food is the first key factor when considering storage times. The upper cut-off for preventing botulism growth is about pH 4.6. The higher the pH, the more risk you have for inviting unfortunate microbial growth.

Temperature is the swing variable. You are likely much better off (in terms of food safety) losing power in the winter than in the summer. The best advice is to find the coolest part of your house (not freezing) and store all of your unrefrigerated food there.

(This is a good time for a reminder about the Forums & Guilds and in particular the Food Preservation Guild. It’s a good place to post your questions or experience about canning, freezing, root cellars, and so forth. You must be registered to post (to avoid spammers), but registration is free, quick, and easy.)