Pickles are the fast-food industry's new summer sweetheart, or in this case, sour-heart.

On Monday, KFC is launching Pickle Fried Chicken for a limited-time run. Essentially, the fast-food chain will cover its extra-crispy chicken with something its calling "pickle sauce."

In making the snappy move, Louisville-based chain joins others, from packaged-food manufacturers to mom-and-pop eateries, that are seeing green when it comes to pickles.

Earlier this month, Sonic Drive-In's Pickle Juice Slush rolled out nationwide. For snackers, the Trader Joe's market chain sells Popcorn in a Pickle. Potato chip companies, from regional players like McClure's in Detroit to national giants like Lay's, offer pickle-flavored versions of their crackly taters.

For dessert, there's pickle ice cream, a soft-serve hot-weather treat from the Lucky Pickle Dumpling Co. in New York.

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KFC will launch its Pickle Fried Chicken.

The sudden interest in products that make you pucker stems from the public's insatiable craving for menu items that offer a twist.

"When you can add to something non-traditional, you get a sensationalistic kick," said Liz Moskow, culinary director of the Boulder, Colo.-based culinary trends firm SRG.. "It’s surprising and it delights the taste buds. It’s just something a little different, out of the ordinary and unexpected."

In the competitive snack and fast-food worlds, unique tastes boost sales by being unique.

Existing customers return to try something new. New customers are lured by the buzz over items that sound wacky. And pickles have slowly been crunching their way back to the forefront.

Brined cucumbers started making a comeback via the bartending world, where picklebacks -- post-whiskey chasers of pickle juice bring out the sweetness of the booze -- became a hip choice for tipplers in recent years, Bottles of pickle juice are popular among athletes, who say it prevents cramps.

Like all things old that a new again, today's pickle flavor is meant to create a whole new vibe far from the droopy, old-school gherkins of yore.

"Instead of simply adding a few more pickles on its chicken to satisfy pickle-passionate
customers, KFC went full-on pickle," the company said in a statement Wednesday. "In addition to classic dill and vinegar flavors, the sauce features onion and garlic notes,
buttermilk and a white and black pepper blend."