Our fruits and veggies aren't as fresh as you might think

When it comes to some supermarket produce, "fresh" is a relative term.

While apples in the store might be crisp and juicy, there's a strong chance they've been sitting in a warehouse for nearly a year, using a process some farmers describe as "putting the apples to sleep."

Packing and shipping companies rely on "controlled atmosphere storage" to keep apples fresh until they're ready to be sold. In sealed rooms, levels of oxygen, carbon dioxide and nitrogen, as well as temperature and humidity, are regulated to keep apples in a state of suspended animation.

Bananas, meanwhile, are shipped on refrigerated vessels within 36 hours of being picked, which stops the ripening process. Once they've reached their destination, the crescent-shaped fruits are placed in sealed, heated rooms to make them ripen once again.

Credit: jack taylor/Getty Images

Want to preserve your salad greens? Just wash in cold water, dry in a centrifuge, treat with a chlorine-based compound, and place in Modified Atmosphere Packaging, in which levels of oxygen and carbon dioxide have been altered to slow deterioration.

Storing food this way isn't inherently unhealthy or unsafe. In the U.S., facilities that store food for domestic consumption must register with the Food and Drug Administration and comply with related safety requirements.

But fresh-picked fruits typically have more vitamins and minerals compared to stored produce, which loses some of its nutritional punch over time, according to dietary experts.

Refrigerated foods can also lose some of their flavor, as scientists found last year when studying tomatoes. The enzymes of chilled tomatoes are apparently less effective at combining the volatile compounds that are crucial for imparting the tomatoes' flavor.

For the truly freshest of the fresh, check out a local farmer's market instead.