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Health / Safety

How to be picky about produce

June 28, 2010

One of the benefits of summer is seeing supermarkets filled with fresh produce, but do you know how to make the best choices for ripeness or freshness?

Editor's note: The following column was written by Shirley Perryman, an Extension specialist in the Department of Food Science and Human Nutrition. The department is part of the College of Applied Human Sciences at Colorado State University.

Good general rules

There are good general rules, but buying some specific produce can be trickier. First, let’s start with the general rules of thumb:

  • Avoid fresh produce that is limp and wrinkled, bruised or discolored because bacteria can thrive in the bruised areas. One caveat in regard to organic or heirloom produce is while possibly misshapen, it may be good eating quality.
  • Buying more produce than you can eat before it starts to spoil is tempting, especially when produce looks and smells great or the price is good. Buy only enough to use in a few days or plan to preserve it.
  • Avocados and bananas can be purchased green and hard and ripen when left at room temperature for a few days. Refrigerating ripe bananas and avocados can extend their life, but buying under-ripe produce isn’t always the best option. The chemical ripening process for under ripe peaches and nectarines, for example, will be interrupted with premature refrigeration.

Tips for a few of the more confusing fruits and veggies

Buying some fruits and vegetables are more challenging than others; here are tips that will ensure the highest levels of nutrients along with the best flavor for a few of those confusing choices.

Corn

  • Fully ripe sweet corn has bright green and sports moist husks with golden yellow to light brown silk.
  • Undeveloped kernels at the top of the cob may indicate the corn was picked at its peak of sweetness and tenderness. If the kernels are full to the top of the ear, the corn may have been picked past its prime and the kernels may have started to get tough.
  • The most important thing to remember when buying fresh corn on the cob is that sugar begins converting to starch immediately after it is picked, so choose ears that have been kept cool and avoid those that have been sitting in the sun. Heat speeds the loss of sugar.
  • Buy it, cook it and eat it as soon as possible.
  • Leaving the husks on until preparation time retains moisture and flavor.

Cucumbers

  • Choose cucumbers that are symmetrically thinner their entire length and firm with good green color.
  • Fat cucumbers are likely to be full of seeds and may taste bitter.
  • Avoid cucumbers with shriveled or soft ends.

Tomatoes

  • The most flavorful tomatoes are vine-ripened.
  • Locally grown tomatoes may not be as pretty as store bought, but the flavor may be superior.
  • Fragrance is a better indicator of a good tomato than color. Smell the stem end which should remind you of the aroma of a fresh tomato plant. A favorite childhood memory of mine is taking the salt shaker to my grandmother’s garden and plucking the tomatoes from the vine and eating them warm from the sun. The aroma and juiciness both contribute to unforgettable flavor.
  • Store tomatoes at room temperature. Refrigerate only overripe tomatoes for a short time. Refrigeration alters tomatoes’ flavor and texture.
  • If you purchase tomatoes that are slightly green, they will ripen at room temperature. Avoid the temptation to place tomatoes on the window sill because they likely will only soften and not develop their best flavor.

Melons

  • Watermelon should be firm and heavy with a smooth rind.
  • If the watermelon’s underside is yellow, it is likely ripe. If it doesn’t have a well-defined yellow side, it may have been harvested too soon.
  • Despite common practice, thumping or shaking a watermelon does not indicate ripeness.
  • A ripe cantaloupe has thick netting over the entire surface of the rind that can be easily felt. It should have cream-colored ridges and a yellow area on one side where it rested while ripening. The ridges may be smoother on the lighter colored side.
  • If any stem is evident, the cantaloupe was harvested prior to its peak.
  • Smell the stem end of a cantaloupe. You should detect a sweet aroma.
  • Push in gently on the stem end; a ripe cantaloupe should yield slightly to pressure.
  • The rind of ripe honeydew melons is creamy yellow-green to cream colored, has a slightly waxy feel, and, when ripe, feel heavy.
  • Honeydew melons will be firm with a small amount of softness at the stem end and have a slightly waxy feel.
  • Ripe honeydews are fairly large.
  • Avoid melons that are too firm, too soft, have dark blemishes on the skin or are too green.

Peaches

  • Check peaches for their firmness and aroma.
  • A ripe peach should feel firm, not hard, to slightly soft.
  • A peach that has a green cast rather than a creamy color was picked while immature and will not ripen to optimum flavor.
  • Peaches should be stored at room temperature until they are ripe. A very ripe peach will also smell sweet.
  • Ripe peaches may be refrigerated, but refrigerating longer than a few days also will lower the juice content and make them less flavorful.

Contact: Shirley Perryman
E-mail: Shirley.Perryman@colostate.edu
Phone: (970) 491-7051