There's been only one case of mad cow disease in the United States, but it's enough to cause some people to take extra precautions to make the safest choice when they buy beef.

If you're looking for assurance against mad cow disease, the experts said that's not easy to find.

The Bremer family eats a lot of hamburgers, but because of the recent mad cow scare, they now look for organic beef.

"We've looked for it, but it's not really available in supermarkets. You have to go find a specialty shop in order to find it. It makes it a little difficult," Kevin Bremer said.

Consumer Reports Urvashi Rangan is a food labels expert. She said there are only two types of beef that offer a reasonable assurance of safety. One is "organic."

"Organic describes an environmentally friendly farming production method that bans the use of animal byproducts in feed," Rangan said.

Since organic labeling is enforced by the U.S. Department of Agriculture, it's considered safe for consumers. The second label to look for is "biodynamic."

"It's independently verified and also prohibits the use of animal byproducts in animal feed. It's harder to find. You may not find it in your supermarket, but you should look in your local farmer's markets," Rangan said.

As for organic beef, Consumer Reports said a Web site called eatwellguide.org can help you find stores that offer it.

The site doesn't have any information about local stores selling organic beef, but it has plenty of options for online orders.

You can also check the Consumers Union Guide to Environmental Labels for information.

Cattle raised for organize and biodynamic beef are not fed by animal byproducts, which can be a source of mad cow. Those are the only tow labels that guarantee that.