Chobani Inc., maker of the nation's top-selling Greek yogurt, is being bombarded with criticism on its own Facebook page after shrinking the size of its flagship product by almost 12 percent.

Chobani, which revolutionized the yogurt business by popularizing the Greek style, last month shrunk its traditional product from 6 ounces to 5.3 ounces. The downsizing coincided with the launch of Chobani Simply 100 Greek yogurt, a 100 calorie offering that also comes in 5.3 ounce containers.

The new Chobani product followed General Mills' successful new Yoplait Greek 100 yogurt, which comes in a 5.3 ounce container. Chobani said in a statement that 5.3 ounces has become the "category norm" in Greek yogurt. Some Chobani consumers, not surprisingly, aren't too happy about it.

"Have been a loyal Chobani customer for years. . . NOT loving that you downsized. Feeling cheated!" wrote Laura Cordts on Chobani's Facebook site this week. Wrote Allison Hill, "Add me to the list of disappointed customers. I would rather have paid a price increase to keep the same 6 oz. yogurts that I loved." Chobani has responded to consumer concerns on the Facebook site.

In a statement, the company said that "at Chobani, we're very close to our consumers and have heard over the years they were often confused at the (store) shelf when trying to compare nutritionals." The solution: make the flagship product 5.3 ounces and consistent with other Greek yogurt offerings. Chobani will also increase promotions this year.

Greek yogurt went from being just sliver of the yogurt market six years ago to over 40 percent now.

Chobani has ruled the Greek segment, with a market share that's almost four times larger than Yoplait's. Yoplait is still huge in the traditional yogurt market, but traditional yogurt sales have been eroded by Greek.

Yoplait's biggest products, original and light yogurt, still come in 6 ounce containers.