General Mills Inc. will launch a new marketing offensive Monday for its Yoplait Greek yogurt, an attempt to take back precious market share lost in the past few years.

It will be a tough slog. Golden Valley-based General Mills was late to the Greek party, while its rivals — notably Chobani — turned a niche product into the yogurt category's dynamo. And Chobani is on an offensive of its own.

General Mills made progress over the past year by reformulating its standard Greek yogurt and finding success with a new lower-calorie product called Yoplait Greek 100. Still, General Mills, one of the world's yogurt giants, has only a high single-digit share of the U.S. Greek yogurt market.

Yoplait is engaging Chobani head-on in a TV ad blitz, rolling out the time-honored taste test.

In a national "Taste-Off," as General Mills calls it, consumers sampled two Greek yogurts, without being told which was which. One was Yoplait's blueberry, which mixes fruit into the yogurt. The other was Chobani's blueberry, which features fruit on the bottom.

"We are so committed to making a Greek yogurt that tastes great," said Carla Vernón, Yoplait's marketing director. "We feel the commercial is an opportunity for people to taste it for themselves — tasting is believing."

The Taste-Off marketing campaign is also running via Twitter, Facebook and Instagram, with General Mills asking consumers to do their own taste tests between Chobani and Yoplait.

Not surprisingly, Yoplait wins the TV taste test. But General Mills has good reason to highlight taste. Its initial Greek yogurt product was not only a latecomer, but was seen by some consumers as an inferior product. The first Yoplait Greek wasn't made through the "straining" production method common to Greek-style yogurts.

But late last summer, Yoplait released a new strained Greek yogurt, complete with a packaging makeover and a new marketing campaign.

The reconstituted Greek product came on the heels of Yoplait Greek 100, a yogurt with 100 calories, 30 to 40 calories less than a conventional Greek yogurt. Yoplait Greek 100 did $150 million in sales during its first full year, the biggest-selling new Yoplait product in at least 20 years. It provided a spark to General Mills' entire Greek yogurt business.

"Yoplait Greek is performing well with sales up 75 percent [in General Mills' current fiscal year]," Credit Suisse stock analyst Rob Moskow wrote in a research report this month. "But it is still a relatively small portion of the company's yogurt portfolio, and we question whether it has the authenticity to compete with brands like Chobani in the longer term."

General Mills still has a huge chunk of the overall U.S. yogurt business, but the Greek category has grown at the expense of its conventional Yoplait products. The result: "The company is now suffering its fifth year of (overall) market share erosion," wrote Goldman Sachs stock analyst Jason English in a research report last month.

General Mills' success with Yoplait Greek 100 is now getting a stiff challenge from Chobani, which last month released its own 100-calorie Greek yogurt. "We believe the recent launch by Chobani of its Simply 100 line puts (General Mills') most popular Greek yogurt product in the crosshairs for competition," English wrote.

Chobani is also upping its heretofore rather minimalist marketing efforts, including running an advertisement during next month's Super Bowl.

Mike Hughlett • 612-673-7003