Shop at the farmers market for produce picked 24 to 48 hours before hand.

From wilted, slimy lettuce to moldy tomatoes, finding spoiled produce in the refrigerator is an unfortunate experience.

Spoilage, a general term defined as the point when food is no longer desired to be consumed, can be caused by bacteria or microbacterial processes that result when a product is exposed to high humidity or temperature, according to Kevin Keener, professor of food science at Purdue University in West LaFayette, Ind.

But making the effort to shop the right way and put your products away correctly takes it the extra mile, said Melissa Graham, founder of Chicago’s non-profit Purple Asparagus, which works with children and families to promote healthy eating.

“If you spend that extra time to put it away properly, you will be able to keep the produce fresher longer, protecting your investment.”

Here are five tips to help you keep your produce fresh and bacteria at bay:

Farm picked
Food is as its freshest when it has just been harvested, and it reduces in quality as time passes. Shopping at the farmers’ market can be the first step in ensuring fresh, quality goods, said Graham.

“If you’re going to the farmers’ market, you’re probably 10 steps ahead of the process,” she said, “because everything has been picked 24 to 48 hours beforehand. If you’ve got farmers’ market produce, it can last in your fridge for weeks.”

Nell Funk, owner of Evanston’s Now We’re Cooking, a culinary center that offers classes and events, suggested buying in bulk at the markets to have fresh products throughout the year.

“Use some fresh and put some away,” she said. “Make jams and chutneys, herb vinegars and pestos. Utilize bulk product and have it throughout the year.”

Shop Smart
When shopping for produce, whether at the market or at a grocery store, Graham said to look for firm products that don’t have any yellow tints, softness, or wrinkles on them. And make sure to pick products that have no visible damages or bruises on them.

The skin of fruit and vegetables shields it from outside bacteria. There is a “protective layer on the outside of apple,” and other fruits and vegetables, said Keener. “The bacteria are looking for the same things we like, they are looking for sugar and nutrients. Once the outer layer is damaged there is nothing to stop bacteria.”

Ask about safety
Whether at the farmers’ market or grocery store, ask about the food safety program and how the produce was handled during processing and storage. Look for products that are picked fresh and kept under refrigeration methods.

“I ask what their food-safety program is, and many are willing to share information about their programs,” said Keener. “That’s the person I want to buy from. If I’m going to be eating the product, I want to know they are aware of food safety.”

Store it right
Use the crisper the way you should, said Graham. “There is a high humidity and a low humidity. The high humidity is for your greens and your herbs, and the low humidity is where you put your apples and harder vegetables that don’t have as much water content.”

Store fruits and vegetables in airtight containers, especially once produce has been sliced. “If you wanted to preserve the crispness, I would look to get these package containers designed for vegetables and fruit storage, which eliminates high moisture loss,” said Keener.

He emphasized that once produce is sliced, which exposes new areas to bacteria, the items become potentially harmful, and need to be stored properly and in refrigeration.

Crisp it up
Carrots can loose their structure and become soft in the refrigerator due to a loss of moisture, Keener said. “The reason those go soft is because when you harvest them they have a high amount of water. Although the fridge has a high amount of humidity, you have to keep humidity at about 100 percent,” which cannot be done, he said.

He suggested peeling flabby carrots to remove any surface contamination, and then placing the peeled carrots in a container of ice water for several hours. He said they “will reabsorb a certain amount of water and become crisp again.”

Another way to use of ice water is for keeping herbs fresh. “A really great way to store herbs is in a cup full of water,” said Graham. “I like to keep the plastic produce bag over the cup, and that can keep fresh cilantro or parsley up to two weeks.”

Bring on the freeze
To extend shelf life, try freezing said Nell Funk. “It’s great for something like root vegetables,” she said. “They will last all winter, which is a great way of preserving the freshness.”“

“The faster produce is frozen, the more like the fresh produce it’s going to be,” said Keener. To do this at home, he said to place a thin tray near the fan of the fridge until cold, then lay the item out in a think layer and place in the freezer.

If you purchase a large amount of an item, Keener also suggested asking a local restaurant to use their freezers, which may be equipped for quick-freezing, during a slow period.