WASHINGTON, D.C. — The U.S. Senate voted Tuesday evening to prevent putting any limits on serving potatoes or other vegetables in school meals.

The action taken by the Senate after bipartisan agreement on the issue Tuesday evening was the result of an amendment by Sen. Susan Collins, R-Maine, and others from leading potato-producing states.

Collins said in telephone interview that she was elated by the vote and that it will send a strong message to the U.S. Department of Agriculture on the issue.

The way the amendment is worded — blocking the department from limiting potatoes — would give USDA flexibility to regulate the preparation of potatoes when it issues the final version of its new school nutrition guidelines.

Collins, along with Sen. Mark Udall, D-Colo., introduced the amendment to the Senate’s agriculture appropriations bill with support from co-sponsors including Sen. Olympia Snowe, R-Maine, and senators in Idaho, New Hampshire, Nebraska and Oregon.

Collins said the proposed changes “would have imposed significant and needless costs on our nation’s school districts at a time when they can least afford it.”

Snowe agreed, calling the amendment “vital.”

“The USDA’s track record on this matter is as disturbing as it is wrong-headed,” said Snowe. “The USDA’s recommendations are not based on sound nutritional science and contradict their own 2005 and the most recent 2010 Dietary Guidelines for Americans. Limiting nutritional and cost-effective meals for our children when nine out of ten Americans are currently not achieving the recommended vegetable and fruit consumption, would deny our nation’s youth access to nutrient-rich foods as part of the National School Lunch and School Breakfast programs.”

Earlier this year, the U.S. Department of Agriculture proposed new nutrition guidelines promoting more fruits, vegetables and whole grains while banning foods with trans fats and limiting starchy vegetables such as potatoes, green peas, lima beans and corn to a total of one cup per week in the National School Lunch Program. The proposed changes also sought to ban the starchy vegetables from the School Breakfast Program altogether.

Speaking on the Senate floor on Monday afternoon, Collins noted that the USDA released guidelines last year calling for Americans to eat more vegetables. Officials from the USDA noted at the time that dietary intake of nutrients such as potassium, dietary fiber, calcium and vitamin D were “low enough to be of public health concern for both adults and children.”

“Since USDA is concerned about a lack of these nutrients in the American diet, it would make sense for the department to promote good sources of these critical nutrients,” Collins said. “Yet, the department’s proposed rule would limit vegetables that are good sources of these nutrients. USDA should not limit their availability, but instead should encourage their healthy preparation.”

Collins, Snowe and U.S. Rep. Mike Michaud, D-Maine, have maintained that it isn’t the potato that is unhealthy, it is how people tend to prepare them.

One medium-size baked potato has just 110 calories and provides 620 milligrams of potassium if eaten with the skin, according to figures from the Presque Isle-based Maine Potato Board. It also contains more vitamin C than one medium tomato and has 15 percent of the daily recommended value of dietary fiber.

The board has battled to quash the assumption that potatoes are unhealthy and several years ago launched a major advertising campaign to promote the nutritional benefits of the potato.

Collins said on Tuesday evening that she found that she had to do “a great deal of education” about the nutritional benefits of the potato in the nation’s capital as advocates and government officials maintained that children get enough potatoes already and should have more diversity in their diets.

“USDA’s proposal was about helping kids to eat a very wide variety of vegetables and I think that point has been lost in all this,” said Margo Wootan, director of nutrition policy at the advocacy group Center for Science in the Public Interest, which pushed for the standards. “Other vegetables have a hard time competing with potatoes.”

Members of Maine’s congressional delegation have been fighting for the potato for more than a year.

Last year, government officials said participants in the U.S. Department of Agriculture’s Women, Infants, and Children program, which serves low-income pregnant women and their children, couldn’t use federal money to buy white potatoes.

Snowe and Collins also have promoted the testimony of Maine school lunch program directors who have spoken about how youth in their districts enjoy baked potato bars that allow them to top their spuds with salsa, broccoli and vegetarian chili, and how potatoes also are a vital part of soups, chowders and dishes such as shepherd’s pie which are not fried.

“I found it ridiculous that if this rule were to go into effect, a school serving a medium baked potato on a Monday would be prevented from serving a full portion of any potatoes or corn for the rest of the week,” Collins said Tuesday evening.

Snowe pointed to information provided by Doris Demers, director of school nutrition at York and Kittery schools, who said that those who believe that schools only serve students french fries are mistaken.

“Today, most potatoes served in schools are baked, not fried,” said Demers. “Like 80 percent of schools nationwide, the deep fryers in York and Kittery schools were removed years ago. In my 18 years working in school nutrition, I have never seen fryers in a Maine school nutrition program.”

The House passed a similar bill earlier this year including language that would ask the USDA to rewrite its school lunch rules entirely. In the coming weeks, the House and Senate could go to conference to work out differences between their respective bills.

But Collins is hopeful the USDA simply will rework its guidelines to allow schools to choose what vegetables they serve.