The government has new rules for preventing food poisoning in fresh-cut produce, but companies don't have to follow them.

Fruit and vegetable-related outbreaks of food poisoning are on the rise and in recent months have struck in spinach, tomatoes, lettuce and cantaloupes.

In the new, voluntary rules, announced Monday by the Food and Drug Administration, fruit and vegetable processors are urged to adopt food safety plans similar to those in the meat industry.

"We've never before formally recommended that the industry adopt regulations such as" the meat industry's, said Nega Beru, director of FDA's Office of Food Safety. "So this is a first."

The difference is that controls in the meat industry are mandatory. Slaughter and processing plants are required to take a scientific look at vulnerable places in the production chain and do constant monitoring of those points. And the Agriculture Department inspects the plants daily.

Food safety advocates and the produce industry are calling for greater government oversight of fruits and vegetables.

The new guidance is "totally unenforceable," said Caroline Smith DeWaal, director of food safety at the Center for Science in the Public Interest, an advocacy group.

"While a grower or processor may chose to use the guidance one week, they could choose not to use it the next, and there's nothing the government can do if the grower or processor chooses not to use the standards," she said.

Rep. Rosa DeLauro, a Connecticut Democrat who heads a subcommittee on food and farm spending, said the FDA guidance "merely tells growers what they already know."

Last fall, an E. coli outbreak in spinach killed three people and sickened nearly 200, and an outbreak of salmonella in tomatoes sickened more than 180 people.

At a field hearing Monday in Wisconsin, Sen. Herb Kohl, D-Wisc., said outbreaks are on the rise for many reasons -- growing imports, more widespread distribution, lack of inspection and growing consumption.

During the hearing, Tom Stenzel, president of United Fresh Produce Association, pledged to see the guidelines followed in every processing operation in the country.

Fresh-cut produce includes shredded lettuce, sliced tomatoes, salad mixes, peeled baby carrots, broccoli florets, cauliflower florets, cut celery stalks, shredded cabbage, cut melons, sliced pineapple, and sectioned grapefruit.