Introduction to Food Storage

Some foods are very sensitive to storage conditions. Others are more forgiving. Some have specific humidity, temperature, and container requirements. Others are more adaptable. This article will explain the basics of food storage.

Food Storage: Quality and Safety

The reason to pay attention to food storage is that how we store food impacts not only its quality, but also its safety. Some foods even come with expiration dates marked to give consumers a clear idea of the limits of safe or tasty use. The factors that affect the safety of food include the humidity, the temperature, exposure to light, and the container used.

Some foods, like dried fruits in re-sealable foil packets and most unopened canned and bottled goods can be stored at room temperature on a cupboard or pantry shelf, where room temperature is expected not to rise above approximately 70º F (21ºC).

Bottled items can be kept in the original container, whether kept on the shelf after opening — as you might do with vinegar, honey, or oil —or refrigerated —as you would do for mayonnaise, salad dressing, jams and jellies, olives, etc. Items that are purchased in vacuum-sealed cans should — for the most part — be moved to a new, airtight container before being stored in the refrigerator. Acidic foods in particular, such as pineapple and tomatoes, should not stored in an original metal container after opening as a chemical reaction begins upon exposure to air, which can cause the container to rust.

Humidity

Too much humidity, especially when combined with warm temperatures, can cause certain foods — like crackers, chips, cereals, and flours — to go stale. It can cause others —like potatoes, garlic, or onions — to rot. This is why it is best to either reseal crispy snack foods, cereals, and flours in their original container or transfer them to an airtight container. Potatoes, garlic, and onions benefit by being removed from plastic bags and put to store in a cool, dark place with air circulation. Ceramic onion and garlic keepers keep these items in the dark and have holes to allow for air circulation. Potatoes can be stored in bins with holes in the sides.

Light

While some foods generally do better in the dark, some are particularly sensitive to light, and their quality is diminished by exposure. This may not occur to people, because several of the products in this category are characteristically sold in transparent/translucent containers. Orange juice and milk maintain their quality best, both in terms of nutrition and flavor, when stored in light-blocking material. Spices, too, are particularly sensitive to light, and should be stored in containers that are airtight and lightproof.

Temperature

While some foods can cope with the fluctuating range that we call room temperature, some foods need a controlled temperature environment in order to maintain quality. These are the foods that we refrigerate, freeze, or keep in a root cellar.

Refrigerator temperature should be between 33º and 40º F (1º to 4º C), while the freezer temperature should be below 0º F (-18ºC). Moving a food item that preserves its quality when frozen — not every food can be frozen properly — in proper packaging, from the refrigerator to the freezer can extend its life from a few days to a number of months. A useful chart of cold food storage can be found at most state extension service websites, for example, the one at Clemson University in South Carolina is helpful.

While most foods give specific instructions for refrigeration and freezing on the label, there are some foods that usually go unlabeled, but may also maintain quality better when kept cold. These include:

• Nut oils — keep best when refrigerated
• Nut flours — keep best when frozen
• Cornmeal — keeps best when frozen
• Hard and grated cheese — last longer when frozen
• Bread yeast — lasts longer when frozen

Containers and Wraps

There are plastic and glass containers, as well as plastic wrap and foil and plastic bags —both those used with twist ties and those with a zipper seal — that are all used to package food. Each has advantages in specific situations.

• Glass and foil may be used for reheating food in the oven, when removed from storage.

• Glass and specially designed plastic wrap and food storage bags may be appropriate for microwaving or may be appropriate only under certain specific circumstances. To ensure safety, check the box or check with the manufacturer. Do not use any plastic product in a microwave that is not proclaimed to be “microwave safe.”

• Food storage bags can allow you to fit liquids into spots in a refrigerator or freezer that a solid container would render impossible.