While it is hard to keep track of which yogurt maker has the latest lawsuit fermenting in court, one thing is certain: Chobani is not backing down from speaking out about its rivals' use of artificial ingredients, and its rivals are fighting back.

Chobani's new ad campaign for its Simply 100 yogurt launched Jan. 6 and calls out certain ingredients used by competitors Yoplait and Dannon in their light Greek yogurts. The campaign is Chobani's latest attempt to push its products as more natural than rivals, but the rivals say using ingredients such as potassium sorbate and sucralose is safe and say Chobani's efforts amount to false advertising.

Soon after Dannon saw Chobani's advertising, which included calling Dannon out for its use of sucralose, it sent a cease-and-desist letter to Chobani. Then, Chobani sued Dannon in federal court over its rival's attempt to block the Greek yogurt maker's suggestive new advertising.

Chobani filed a suit in U.S. District Court for the Northern District of New York on Jan. 8.

"Chobani is seeking a declaration from the Court that Chobani's advertising for its Chobani Simply 100 Greek Yogurt products is not false, misleading, disparaging or deceptive and that Chobani's reliance on the USDA nutrient database to support its claims that its Greek Yogurt contains substantially less sugar than regular yogurt are not false or misleading," the company said in the statement issued Sunday night.

The Greek yogurt company released a statement about the suit late Sunday night, after running new full-page ads (similar to the one shown here) in national newspapers Sunday as part of the Simply 100 campaign launch.

"We believe in truthful and honest marketing and advertising, and we are therefore very disappointed that the Chobani campaign misleads and deceives the public about the healthfulness and safety of our Light & Fit brand," a Dannon spokesman said, adding that sucralose is an FDA-approved ingredient. "We intend to pursue all available avenues to address Chobani's misleading and deceptive marketing."

Dannon isn't the only one pushing back. General Mills, the maker of Yoplait yogurt, filed a suit of its own on Sunday in U.S. District Court in Minnesota, alleging false advertising under the Lanham Act. "The statements made by Chobani in their latest attempt to sell more yogurt are inaccurate and misleading, and we don't think consumers appreciate that kind of approach," General Mills spokesman Mike Siemienas said in a statement Monday.

Chobani Chief Marketing and Brand Officer Peter McGuinness said though he's not surprised by his rivals' actions, he's "disappointed that Dannon and General Mills are focused on stopping people from having the facts about artificial sweeteners and preservatives."

Mr. McGuinness says the campaign is about choice. "Consumers have the right to know what's in their cup. This campaign is fundamentally about choice -- the choice between natural ingredients versus artificial ingredients."

Dannon, meanwhile, continued to stand by its products.

"We believe in truthful and honest marketing and advertising, and we are therefore very disappointed that the Chobani campaign misleads and deceives the public about the healthfulness and safety of our Light & Fit brand," spokesman Michael Neuwirth said in a statement issued Monday morning. "Like many reduced-calorie foods, Light & Fit Greek nonfat yogurt contains sucralose, an FDA-approved ingredient that has been safely and widely used as a sweetener in foods for more than 15 years. The truth is, we carefully craft our recipes to make our products not only delicious, but nutritious too. Dannon is a beloved American brand and as a company we have always prioritized the health and safety of our consumers, and to suggest anything to the contrary is false and damaging. We intend to pursue all available avenues to address Chobani's misleading and deceptive marketing."