As if General Mills Inc. hasn't had enough problems in the Greek yogurt market, with its venerable Yoplait brand falling well behind the competition.

Now the packaged foods giant is in a court battle over whether its Yoplait Greek yogurt is, well, Greek yogurt, or even yogurt at all under federal food regulations.

A Chicago resident has sued General Mills claiming it isn't, and the Minneapolis-based law firm Zimmerman Reed is angling to make the case a class action. General Mills argues that the suit misinterprets federal regulations, and that its Greek yogurt is indeed yogurt.

The Golden Valley-based packaged foods maker, one of the nation's two yogurt giants along with Groupe Danone, has asked that the suit be thrown out. A federal judge in Minneapolis is scheduled to hear arguments on that request Friday.

No-fat or low-fat Greek-style yogurt has gone from a niche product to dean of the dairy case in the past two years. It's where the growth is in the roughly $5 billion U.S. yogurt business. But General Mills got into the Greek market late and is playing catch-up.

Compared with mainstream U.S. yogurt, Greek-style is a thicker, richer yogurt with at least twice as much protein. Most Greek yogurts have these characteristics because they are strained to remove liquid whey, the watery portion of milk.

General Mills, however, makes its Greek-style yogurt with a thickener called "milk protein concentrate," which comes from filtering skim milk to remove non-protein elements.

Plaintiffs' argument

Chicagoan Martin Taradejna and other "similarily situated" consumers claim in a suit filed this spring that General Mills, by using milk protein concentrate, has misbranded and misrepresented its Greek product as yogurt.

Consumers were harmed because they were paying a premium for General Mills Greek yogurt compared with regular yogurt, the plaintiffs argue. Greek yogurt usually costs about 75 cents more per 6-ounce container than traditional yogurt.

Many foods have a federal "standard of identity," and the one for yogurt does not include milk protein concentrates, the plaintiffs argue.

"Standardized foods like milk, cheese and yogurt must strictly conform to [their standard of identity] in order to be labeled, marketed and sold as those foods," said a plaintiffs' court filing. Foods that don't comply with identity standards must be labeled "imitation."

Plaintiffs' lawyers point out that the U.S. Food and Drug Administration found in 2002 that cheese is misbranded if it contains milk protein concentrate because the ingredient is not included in cheese's standard of identity.

General Mills' riposte

In court filings, General Mills argues that "under the current standard of identity, it is the FDA's official view that yogurt may contain milk protein concentrate."

The company says that the FDA doesn't specifically limit milk protein concentrate as an ingredient in yogurt. And at a 2004 national food safety conference, an FDA representative was specifically asked whether milk protein concentrate can be used in yogurt, and the answer was "yes."

The FDA, asked specifically by the Star Tribune if milk protein concentrate is allowed in yogurt, didn't respond to that question.

Greek yogurt commands a 35 percent share of the U.S. yogurt market, up from 15 percent at the end of 2010 and about 1 percent in late 2007, according to a recent report by stock analyst Alexia Howard of Bernstein Research.

The upstart Chobani brand by far leads the Greek yogurt category with a 47 percent share. General Mills has only a 6 percent share of the Greek market, according to the Bernstein report.

General Mills recently unveiled a major yogurt product offensive, including Yoplait Greek 100, a new 100-calorie Greek-style yogurt. Greek yogurts typically have 140 calories to 160 calories.

At a General Mills investment conference earlier this week, Yoplait USA President Becky O'Grady said Greek 100 would be a "strained" yogurt. She didn't elaborate further, though strained is usually associated with Greek yogurt sans thickeners such as milk protein concentrate.

Yoplait Greek 100 isn't on store shelves yet, but on General Mills' website there's a picture of it. The ingredient list makes no mention of milk protein concentrates.

Mike Hughlett • 612-673-7003