Atlanta ? Federal prosecutors have begun a criminal investigation into fraud allegations raised by a whistleblower’s lawsuit against Coca-Cola Co.

The world’s largest soft drink company announced Friday that the U.S. Attorney’s Office was investigating. Also Friday, Burger King said it would phase out the sale of Frozen Coke at its fast-food restaurants and stop using Coke’s frozen carbonated beverage machines.

Among the allegations raised in the whistleblower’s lawsuit was that Coke employees rigged a market test at Burger King outlets to inflate the popularity of Frozen Coke, the slush drink sold at restaurants, convenience stores and other locations.

The whistleblower also said some of Coke’s machines that make Frozen Coke were defective, a claim Coke denies.

Coke’s statement about the investigation did not provide any details, but said it would cooperate with the inquiry.