As in so many cases, moisture is the potential villain here. This popular vegetable, which is one of the most contaminated foods on the market, will last about a week if it’s stored in the refrigerator in a sealed plastic bag with a couple of sheets of paper towel to absorb excess dampness. Don’t wash kale until you’re ready to eat it, even if you think you’re drying it thoroughly, as this may cause the leaves to wilt, or encourage mold to form.
Fresh limes last for two to four weeks at room temperature and up to two months in the refrigerator. The problem is that it’s hard to tell how old limes are already by the time they reach the grocery store, so fruit that is kept for more than a week should be monitored. Limes develop mold less often than lemons or oranges, but “spoil” by turning brownish and hard, with their juice virtually drying up. Cut limes should be used immediately unless they’re refrigerated, in which case they’re good for a couple of days.
Veteran picnickers know that potato salad and other mayonnaise-dressed dishes can be among the most dangerous things to eat at an outdoor meal, because eggs are a fertile medium for the development of bacteria. In any dish containing mayonnaise, the mayo will almost certainly spoil before any other ingredients. The safest procedure is to keep mayonnaise-dressed foods refrigerated until mealtime, then return uneaten portions to the refrigerator immediately afterwards, keeping them for no more than three days.
Anyone who has ever cooked mushrooms knows that they give off a lot of liquid when they’re heated. Their high moisture content invites mold and mildew to form. Wild varieties like morels, black trumpets, and chanterelles may be particularly susceptible. Ideally, mushrooms of any kind should be eaten as soon as possible, though they may be stored in paper bags, in the refrigerator, or in a cool, dark place, for about a week. Packaged pre-sliced mushrooms may go bad a few days sooner.
While most varieties of nuts will last for six to nine months in the pantry and up to a year in the refrigerator, pine nuts — which are actually the seeds of certain kinds of pine trees — have a high oil content and tend to turn rancid after a couple of months at room temperature and three or four months refrigerated.