WASHINGTON (AP) -- The Food and Drug Administration is challenging makers of alcohol-infused energy drinks to prove their beverages are safe, citing complaints that the products can cause risky behavior and injury.

The FDA issued a letter Friday to 30 beverage manufacturers, giving them 30 days to provide evidence that the combination of caffeine and alcohol is safe.

"Today the FDA has listed caffeine only as an ingredient for use in soft drinks," said Deputy Commissioner Dr. Joshua Sharfstein. "The agency has not approved caffeine for use in alcoholic beverages."

FDA officials stressed they have not reached a conclusion about the safety of beverages like Joose and Charge. Instead they are trying to understand the companies' legal rationale for marketing the products.

"There are some unusual safety questions raised by the addition of caffeine to these alcoholic beverages," said FDA special adviser Mike Taylor. "So the burden is on the companies to provide evidence that supports the conclusion this use is safe."

The FDA decided to take action at the urging of state attorneys general from New York, California, Maryland and 16 other states, who contend the drinks appeal to underage drinkers and encourage reckless behavior. Young adults already are the primary demographic for highly caffeinated drinks like Red Bull.

Larger brewers like Anheuser-Busch already have removed caffeine from their alcoholic energy drinks. Remaining manufacturers include smaller firms like Los Angeles-based Joose Beverage and Portland, Ore.-based Charge Beverages.

Calls placed to those companies Friday were not immediately returned. Other companies receiving the FDA letter include: Mix Master Beverage Co. of Stateline, Nev., Blank Beverages Co. of San Diego, Calif., and Phusion Projects LLC of Chicago.

The market for caffeinated alcoholic drinks is about 1 percent of the total beer industry, making its annual sales about $1 billion, said Eric Shepard, executive editor of trade publication Beer Marketer's Insights.

The companies could fight back against the FDA request by noting that their products already were approved by the Alcohol and Tobacco Tax and Trade Bureau, Shepard said.

However, FDA officials suggested on a call with reporters that the Treasury Department bureau would defer to the FDA on product safety questions. A spokesman for the bureau said the agency requested and fully supports the FDA's action.

MillerCoors in December agreed to remove caffeine and three other ingredients from Sparks, the top-selling alcoholic energy drink at the time. The company agreed to pay $550,000 to cover the cost of the investigation by 13 state attorneys general.

In June 2008, St. Louis-based Anheuser-Busch, now Anheuser-Busch InBev, agreed to reformulate its Tilt and Bud Extra drinks to remove the stimulants as part of a settlement with 11 attorneys general.

Consumer health advocates like the Center for Science in the Public Interest, which has filed lawsuits against makers of alcoholic energy drinks, cheered the FDA action.

"These beverages create alert drunks," said George Hacker, the center's director for alcohol policy. "People think they can drive, think they can handle things because they're not feeling impaired, when in fact they are."

The announcement Friday marks the second time in less than a month that the FDA has taken up an issue championed by Hacker's group. Three weeks ago, the FDA warned that nutritional logos on groceries are misleading consumers about the actual health benefits of processed foods.

"It's really refreshing to see government performing its duties once again," Hacker said.

President Barack Obama tapped FDA Commissioner Margaret Hamburg and Sharfstein earlier this year to try and restore the agency's credibility, after a string of bungled food and drug safety issues.

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