NEW YORK — As fruit and vegetable prices soar, you can save money by taking some extra time in the produce aisle to make sure bad apples aren't sneaking into your grocery cart.

The average U.S. household throws out nearly a quarter of the fruits and vegetables it buys. For a family of four, that adds up to about $500 each year, according to a study by the University of Arizona.

One reason for the rampant waste is that many people aren't sure how long they can safely keep fruits and vegetables. If your fruit has gone bad, however, you'll generally know — if not from telltale dark spots, then by smelling or squeezing it.

Knowing how to pick and store your produce can help extend shelf life so it doesn't get to the point where you have to throw it out. The best methods vary depending on the fruit or vegetable, but a few rules of thumb generally apply across the board.

The first step is to immediately inspect your goods once you get home and pluck out any spoiled specimens.

"It really is true that one bad apple can make the entire bunch go bad," said James Parker, who's in charge of buying produce for Whole Foods Markets.

That's especially true for soft fruits such as peaches and nectarines. And the higher the sugar content, the more likely a fruit is to spoil faster.

After weeding out any rotten pieces, storing produce in optimal conditions can extend freshness. Take note of how fruit and veggies are displayed at the supermarket — it's usually a good indicator of how they should be kept at home.

Cherries, for example, are packed and shipped in cold temperatures — so refrigeration is the best option for storage.

"The minute you break that environment, the decomposition begins," Parker said.

Tomatoes, on the other hand, break down more quickly when refrigerated. So if you're not sure of the best way to store a particular fruit or vegetable, ask a produce department manager or check online.

Remember that most produce — especially mushrooms — is sensitive to moisture and stores better unwashed. A good rinse is best saved for right before eating or cooking. Adding citrus juice to pre-cut fruit can also keep them fresh longer.

Buying regionally and seasonally can blunt escalating prices, too. Right now, for example, berries, peaches and nectarines abound at reasonable prices in most parts of the country.

Shoppers have good reason to be picky about produce these days. Overall, food prices are expected to rise as much as 5.5 percent this year, with a slightly bigger increase for food that people make at home and a smaller increase for food in restaurants, according to the U.S. Department of Agriculture.

Fruits and vegetables are among the hardest hit by rising food prices, since they are processed less (if at all), which makes it harder to spread around cost.

Still, people often end up buying more produce than they eat, and end up discarding it when it goes bad.

One reason is that "people want to perceive themselves as eating healthier than they do," said Timothy Jones, author of the University of Arizona study on food waste.

Grocery shopping typically occurs on the weekends, when ambitions soar for wholesome recipes chock full of vegetables. When the work week kicks into gear, however, people run out of time and fall back on frozen dinners or takeout.

By the end of the week, they're often left with produce that's turned to mush.

The result is enormous waste. While a couple of broccoli bunches may seem cheap, the price can add up when you're throwing it all away.

Making matters worse is the tendency to buy in bulk — which ironically happens more often when people are trying to save.

"You need to be realistic on how many people you're feeding," Parker said.

Finally, knowing when to give your produce the heave-ho can help save. People often throw out food prematurely because they're not sure whether it's still OK to eat.

Parker said the best test is to use your senses, as you would in picking out produce.

"If it's soft and rubbery, it might not be good. Broccoli and asparagus, for example — you can tell by the smell when it goes bad," Parker said.