Take the 2-minute tour ×
Seasoned Advice is a question and answer site for professional and amateur chefs. It's 100% free, no registration required.

Federal food safety guidelines advise against leaving food in the "danger zone" (4-60° C / 40-140° F) for more than 2 cumulative hours. However, not all food needs refrigeration; some obvious examples are bread, peanut butter, unpeeled potatoes or onions, even some pastries such as fruit pies.

How do I know if a particular food is immune to this danger zone and thus safe to store for several hours or days at room temperature? What about longer-term storage?


Note to answerers - this is intended to be a "canonical" or "reference" question on food safety. Please do not answer unless you can support it with a trusted source. General guidelines are also preferred over a list of specific foods.

share|improve this question
    
Perhaps cooking.stackexchange.com/questions/2642/… would be a good spot? Disclosure: I wrote the question, long ago. –  Peter V Aug 23 '11 at 0:50
    
Incidentally, I believe a large-ish table with notes is the right way to answer this question. For example, storage onions and potatoes are measured in months. –  Peter V Aug 23 '11 at 0:51
    
@Peter: I definitely appreciate what you were trying to do with your question. It's very general, though, and I'd like to attack this issue with a bit more precision, since this is a Q&A site and questions with specific (albeit long) answers tend to fare best over time. A table would be a great thing to maintain as a wiki; alternatively, it's not necessary to include detailed times for each, just the particular factors that protect perishable food in the short term - and there are a fairly limited number of those. –  Aaronut Aug 23 '11 at 0:55
    
This makes a lot of sense. I'm probably not the person to launch it, though. :) –  Peter V Aug 23 '11 at 21:08

3 Answers 3

Pie is a good example: fruit pie tends to keep for a good while at room temperature. I have found many sites which stridently claim this not to be the case, and many grocery stores that leave their bakery pies at room temp for about three days (even psycho Mrs. Cookwell says 2 days is fine). I'm siding with the grocery stores. Nut pies tend to last longer still, because they're drier: the presence of dairy and eggs is counteracted by the higher concentration of sugar.

Likewise cake, though it can vary depending on your frosting...The more things besides fat and sugar in your frosting, the more it needs to be refrigerated. In most cases cake will stay edible longer than you'd want to eat it. Again, grocery stores only bother to refrigerate decorated cakes, or ones with cream cheese icing.

Most store bought condiments are fine at room temperature. Obviously not mayonnaise, or anything creamy, but ketchup, mustard, A-1, worstershire...They last a good long time unrefrigerated. Likewise soy sauce, fish sauce, and some of the more popular asian condiments.

I've never seen a pepper sauce (e.g. Tabasco) that needs refrigeration, and they'll last for years, though the color starts going off after a while.

There is no bacterial risk to leaving fruits and vegetables out, but this will dramatically increase the rate of spoilage. The exceptions are root vegetables, and bananas. Root vegetables will last a long time in a cool dark place, so just lump 'em in your garage if you're not going to eat them in the next week or two. And bananas will go south at the same rate regardless (though you can freeze them for future banana bread).

Fresh eggs (like, straight from the chicken) will last a couple of weeks without refrigeration (make sure they're not fertilized, or you may wake up to find baby chickens in your kitchen). The rule of thumb is "Every day unrefrigerated is like 5 days refrigerated." Once eggs are cracked, you should use them immediately.

I'd trust store bought eggs left out on the counter to eat, though its not good to let refrigerated eggs get warm again. Eggs have a wide array of natural antimicrobial tendencies, though the processing store bought eggs go through removes some of this. (citation). An easy way to test for internal contamination is to see if the egg floats in water. If it floats, toss it.

Bacon grease keeps a long time unrefrigerated, as does any sort of fat really, as long as it's strained and filtered. With fats you're more worried about them going rancid, which is a function of light and air (its a type of oxidation), so store your fat in a dark place, in a sealed container. (citation)

Butter can last several days unrefrigerated (it should be covered). I'd say as much as a week, but I have no way of knowing because it never lasts that long. It's much more likely to oxidize (see above) and go rancid than to pick up a significant bacterial colony.

share|improve this answer
    
I looked up some info about the cream cheese frosting, because I make this a lot. Basically, you have to have enough sugar to stabilize it, otherwise it is just a sweet dairy product. My recipe uses about 1:4 cream cheese to powder sugar by weight. So it lasts a long time. Some store ones probably won't. Here is the link with its citations: link Also, most condiments generally should be refrigerated after opening to extend use. If you go through a bottle of ketchup a week though, this probably is not an issue. –  JSM Jun 4 at 17:36
    
@jsm: Oh, I don't think it'll go bad. I just think it tastes better, and also, maybe, that it doesn't have as much structural integrity if its warm, so keeping it cool keeps your decorating looking better. –  Satanicpuppy Jun 5 at 12:25
    
I mostly use it for a carrot cake recipe (that I haven't made in years), or for frosting cookies at christmas. For the latter, it's 3 oz cream cheese, 1 tsp vanilla, and I believe 2-2.5 cups (about 9-10 oz) powdered sugar. It stays soft for a day or two, but forms a nice crust after that. This makes transportation and packaging easier. I have also eaten them after a couple of weeks with no discernable change in flavor; maybe just a little dryer. For cookies I give out though, I try to get it out by day 3, so they have a week or so to eat them. Not that they last that long. –  JSM Jun 6 at 18:14

Simple: Walk your favourite super-market's corridors; some food is in the fridge, some other not.

Follow suit and watch out for the expiration dates: they are meant to define expiry under such conditions.

share|improve this answer
    
An excellent point -- a grocery store would get shut down if they were storing things improperly. Of course, there are cases where they'll refrigerate things that don't need to be chilled, just to make it seem like it's more fresh (eg, soy & most nut milks; they recommend serving it chilled, but it doesn't need to be stored that way long-term) –  Joe Sep 16 at 1:29

Most health codes will have concepts of 'high risk' vs. 'low risk' foods. 'Low risk' are the foods that can be held at room temperature for longer periods of times with a low risk of getting people sick. It includes things such as:

  • Really dry things (eg, uncooked grains, pasta or beans, bread, cookies, crackers, jerky, etc.).
  • Specifically preserved things (smoked fish, pickles, salami, etc.)
  • High sugar, salt or acid items (syrup, most candy, jelly, soy sauce, pickles, etc.)
  • Canned or jarred items

Of course, you get into trouble as there's always a chance of cross-contamination, so even things like fruits & vegetables aren't always put into this category. And leaving things out and exposed to air for extended periods of time isn't a good idea, either.

Lists out there vary, as they serve different purposes. For instance, foods that you're allowed to make at home and sell in Vancouver, BC doesn't include preserved meats, while lists of what grocery stores don't need to keep chilled typically assume that salami and other preserved meats are being prepared in commercial kitchens and sealed to prevent contamination.

It's possible that your local health department may have specific things that are known to be a problem locally. (eg, if there were specific food recalls or issues with contamination).

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.