Anheuser-Busch has hit back in its latest row with Miller Brewing, labelling its rival as "desperate".

The two brewers have become embroiled in another spat in the US with Miller accusing A-B of changing the recipe for its Bud Light brand after witnessing the growing sales of Miller Lite.

Miller, the US arm of brewing giant SABMiller, said it had monitored the taste profile of Bud Light and there were "significant increases" in the brand's bitterness and carbonation levels. Miller argued this "reversed a 15-year trend" in which the bitterness levels of Bud Light had almost halved.

However, A-B has insisted that it had not made a "formulation change" in the way it brewed its beer.

"Bud Light is the No. 1 selling light beer in the world, and it has been for more than a decade," Douglas J. Muhleman, A-B group vice-president for brewing operations, told just-drinks. "It's a winning formula and we haven't changed it."

"Our brewmasters depend on tasting the beer, not lab analysis, as the basis for brewing our beer. To suggest that we have made a formulation change in the way we brew our beers is simply false."

He added: "Clearly this is just another marketing ploy and appears to be a desperate move by a company that has lost market share for more than six months, while our brands have continued to gain share, according to IRI supermarket data."

Miller's stance followed A-B's moves to block the broadcast of three new Miller Lite ads on cable networks in the US. The commercials promote Miller's claim that its Miller Lite brand "has more taste than Bud Light with half the carbs" but A-B has argued that Miller needs to provide evidence to back up its claim.

A-B has succeeded in blocking the ads on 10 cable stations, which led to Miller moving to give the networks the necessary information to back up its taste claim on Miller Lite.

A spokesman for Miller said the Alcohol and Tobacco Tax and Trade Bureau upheld the taste claim in April and the brewer would "work hard" to protect the claim.

A-B hinted that it might back down in its moves to block the ads. "It is up to the networks to decide what they air," Muhleman added.