"Thank you for suing us."

So reads the headline on full-page print ads that fast-food giant Taco Bell launched Friday as part of a plan to fight back against a lawsuit that charges its taco filling isn't really beef.

The ads, which appear in the Wall Street Journal, USA Today, New York Times and other papers, aim to "set the record straight" and explain what really goes into a Taco Bell taco.

The advertizing blitz comes amid a class-action lawsuit filed late last week in California that claims Taco Bell falsely advertise its products as "beef." The suit claims that the meat mixture used in Taco Bell burritos and tacos allegedly contains so many binders and extenders, it no longer meets the U.S. Department of Agriculture's definition of "beef."

The Alabama law firm Beasley, Allen, Crow, Methvin, Portis & Miles that launched the suit says it had the meat mixture tested and found it contained less than 35 per cent beef.

The firm would not say who tested the meat or give any other specifics of the analysis.

The lawsuit does not seek monetary damages; the plaintiffs simply want the court to order Taco Bell to be honest in its advertising.

Taco Bell says the suit's claims are "absolutely false." The company says its seasoned beef contains 88 per cent USDA-inspected beef. The rest is water, spices and a mixture of oats, starch and other ingredients that it says provides "Taco Bell's signature texture and taste."

"The only reason we add anything to our beef is to give the meat flavour and quality," the company says in the ad.

"We stand behind the quality of our seasoned beef 100 per cent and we are proud to serve it in all our restaurants. We take any claims to the contrary very seriously and plan to take legal action against those who have made false claims against our seasoned beef."

The ad is signed by Taco Bell President Greg Creed.

For the record, the full list of ingredients in Taco Bell's seasoned beef is on its website.

Marc Williams, an attorney and expert in fast-food litigation with the firm Nelson Mullins Riley & Scarborough, said Taco Bell couldn't ignore the lawsuit because it has already generated so much buzz, thanks to the Internet.

Williams told the Associated Press he believes the case is "thin" in potential legal liability.

Lawyers would have to prove that most consumers expect and believe they are getting something other than what Taco Bell actually serves. Most fast-food customers, he said, realize taco meat has other ingredients besides beef.

He also notes that the USDA's guidelines for labelling ground beef don't apply to restaurants. Instead; they apply to meat processors.

With reports from the Associated Press