How to Preserve Fruits and Vegetables

Clean out your refrigerator.

By Kevin RR Williams

HEALTH Stuffing fruits and vegetables anywhere they fit in the refrigerator is not a good idea. From the moment a fruit or vegetable is picked, it begins dying. Initially, residual juices provide a reasonable shelf life. As foods begin to decompose, they give off gases until they rot.

There is a reason why refrigerators have separate fruit and vegetable bins — also why some produce should be kept out of the refrigerator. As many fruits and vegetables ripen, they release a gas called ethylene. This causes neighboring produce to become ripen prematurely. Therefore it is advised to, keep ethylene-sensitive fresh fruits separate from vegetables that emit the gas. Generally, the ethylene producers are mostly fruits and the ethylene sensitive produce is mostly vegetable. The exceptions are watermelon and unripe bananas.

Ethylene-Sensitive

Refrigerated Vegetable Bin

  • Asparagus
  • Broccoli
  • Brussels sprouts
  • Carrots
  • Cucumbers
  • Eggplants
  • Green beans
  • Lettuce and other greens
  • Peas
  • Summer squash
  • Watermelons

Outside Refrigerator

  • Apples*
  • Bananas (unripe)*
  • Potatoes

Ethylene-Producing

Refrigerated Fruit Bin

  • Apricots
  • Cantaloupes
  • Honeydew melons
  • Kiwis
  • Mangoes
  • Nectarines
  • Papayas
  • Passion fruit
  • Peaches
  • Pears
  • Plums
  • Prunes

Outside Refrigerator

  • Avocados*
  • Bananas (ripe)*
  • Tomatoes*

* Apples, avocados, and tomatoes are both high producing and sensitive. So they should be separated from other produce and left out of the refrigerator — on the countertop or place root vegetables in a potato bin. Using this knowledge to your advantage, you can hasten ripening of produce by paring it with an ethylene producer. For example hard unripe avocados might be placed in a brown paper bag with an apple for a day or two. Likewise, a quick way to hasten green banana ripening is to store with an apple.

Related: Secrets to Sensational Salads

Freshly picked tomatoes release huge amounts of ethylene. They therefore experience what is known as “ethylene shock,” whereas the closely related chili peppers show no such effect. Because of the amount of ethylene, tomatoes should not be refrigerated but kept on the countertop. Shop for tomatoes on the vine at farmers’ markets when possible for long-lasting results.

Related: How to Shop For a Refrigerator

Making a soup, salad or sandwich may result in some residual pieces of vegetables. It may seem efficient to place the extra pieces in a plastic bag together or add them to an existing bag of vegetables in the refrigerator. Because of varying rates of decay (ethylene production), the cross-contamination can reduce the shelf life. It is better in my opinion to bag everything separately (especially cut tomatoes).

It goes without saying that separately packaged frozen fruits and vegetables have no ethylene interaction in the freezer. As mentioned in a prior article, you can keep extra pieces of herbs and vegetables together in a freezer bag until you later boil and strain to make soup broth.

How To Distinguish Fruits From Vegetables

To a botanist, a fruit is an entity that develops from the fertilized ovary of a flower. So tomatoes, beans, corn kernels, cucumbers, eggplants, peppers, pumpkins, squash and pea pods are all fruits; so are apples, apricots, mangos, melons, pears, and peaches. Botanically speaking a vegetable, is any edible part of a plant that doesn’t happen to be a fruit, as in leaves (cabbage, lettuce, spinach), roots (beets, carrots, turnips), stems (asparagus), tubers (potatoes), bulbs (onions), and flowers (broccoli and cauliflower).

Are tomatoes fruit or vegetables? Botanical and polical produce definitions differ. In 1886, importer John Nix and colleagues brought a load of West Indian tomatoes at the New York Port. The customs official, Edward Hedden, demanded a ten percent tax (Tariff Act of 1883 levied an import duty on “foreign vegetables.”) Nix, who knew his botany, objected, on the grounds that the tomato is a fruit that should be tax-exempt. The case eventually made its way to the Supreme Court where, in 1893, Justice Horace Gray ruled in favor of vegetable.

“Botanically speaking,” said Justice Gray, “tomatoes are the fruit of a vine, just as are cucumbers, squashes, beans and peas. But in the common language of the people…all these vegetables…are usually served at dinner in, with, or after the soup, fish, or meat, which constitute the principal part of the repast, and not, like fruits, generally as dessert.”

Cambria Bold offers the following tips for storing fruits and vegetables:

For Fruits: Non-cherry fruits, apples, avocados, mangoes, melons, pears, and tomatoes continue to ripen if left sitting on a countertop. Grapes, bell peppers, citrus, and berries deteriorate so refrigerate them. Bananas ripen very quickly, and also speed ripening of nearby fruits.

For Vegetables: Remove rubber bands and ties, trimming any leafy ends to an inch before storing. Make sure the bag you store the veggies in has punctured air-flow holes. Pack vegetables loosely in the refrigerator to hasten rotting. Wash leafy greens before storing by soaking them in a sink full of water. Do not was soft herbs or mushrooms until ready for use.

Preventing Listeria

Listeria is the name of a bacteria found in soil and water and some animals. People usually become ill with a rare disease called listeriosis after eating contaminated food. Listeriosis most often affects unborn fetuses, newborn infants, older adults, and individuals with weakened immune systems. Thoroughly cook all raw foods of animal origin, such as meat to prevent listeriosis and other foodborne diseases, because heat kills L. monocytogenes. Reheat leftovers or prepackaged foods, especially deli meats, until steaming hot. Wash raw fruits and vegetables thoroughly. Do not eat or drink raw (unpasteurized) milk or other dairy products. Though Mexican-style cheeses and other Latin-style soft cheeses made from pasteurized milk have also caused listeriosis have caused listeriosis, do not eat soft cheeses such as Brie, feta, and Mexican-style cheeses, unless they are labeled as made from pasteurized milk.

Considerations for Nightshade Foods

Most commonly studied and consumed nightshade plants are the alkaloid potatoes, tomatoes, and eggplant. Below are key alkaloids in these three nightshade foods.

Nightshade FoodScientific NameKey Alkaloids
TomatoLycopersicon esculentumtomatine, deyhdro­toma­tine
PotatoSolanum tuberosumalpha-solanine, chaconine
EggplantSolanum melongenasolasonine, solar­margine

There rare potential health benefits associated with food alkaloids. Yet, there are also potential problems with excessive intake. Based on a study of potatoes from Mexico, 65-70% of the alkaloids were removed by skinning the potatoes prior to cooking. People who want to lower the alkaloid content of potatoes should cut out any sprouting spots prior to cookin. Exposure to light can increase the alkaloid content of potatoes so store them in a dark place.

Some with forms of arthritis or other musculoskeletal health problems who eliminate nightshades vegetables feel better. A large-scale human research study that suppots this theory is lacking.

Related: End Carbohydrate Cravings

Do not place too much confidence in pre-washed leafy greens. These are residuals from various whole lettuces, spinach and other greens. They have different rates of decomposition due to age and variety. In your refrigerator, some turn brown and give off odors faster than others in the same bag. (A whiff of the contents can resemble the smell of flatulence.) Isolating the good, bad and ugly requires rinsing and separating even though they were pre-washed. When possible, purchase (or grow) whole vegetables to stay A Bit More Healthy.

Related: 11 Benefits of Blueberries — Backed by Science


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Tags: decay, preservatives, refrigerating produce

References
  1. Avoid Premature Spoiling of Fruits and Vegetables. realsimple.com
  2. List of sensitive produce. eris-filter.com
  3. Why You Should Store Some Fruits and Vegetables Separately. thekitchn.com
  4. Ethylene of no effect: Why peppers do not mature after picking. phys.org
  5. Is a Tomato a Fruit? It Depends on How You Slice It. nationalgeographic.com
  6. The Kitchn's Guide to Storing Fruits and Vegetables. thekitchn.com
  7. How Long Is It Really Safe to Keep Foods? (Infographic). health.clevelandclinic.org
  8. Listeria. FoodSafety.gov
  9. Listeriosis - NORD (National Organization for Rare Disorders) rarediseases.org
  10. Which foods are classified as "nightshades," and is it true that foods from this group can potentially contain problematic substances? whfoods.org