WASHINGTON — It’s potato wars showdown week in the Senate.

Sen. Susan Collins, R-Maine, is hoping to get a vote this week on legislation aiming to prevent the U.S. Department of Agriculture from limiting the amount of potatoes that can be served as part of the federal school lunch program.

Collins is teaming up with Democratic Sen. Mark Udall of Colorado on the amendment to the 2012 agriculture spending bill, a proposal which would prohibit the agriculture department from using its funds to impose “maximum limits on the frequency of serving fruits and vegetables in school lunch programs.”

Collins, whose potato roots stretch back to picking them as a youth in the potato country of Aroostook County, says potatoes are a nutritious vegetable that is healthy as long as it served in its baked or boiled or stewed versions, not as french fries.

Collins’ amendment goes farther than one included in the House version of the agriculture spending bill, which merely expresses concern about the proposed rule limiting potatoes as part of the school lunch program. Co-sponsors of the Collins-Udall amendment so far include GOP Sens. Olympia Snowe of Maine, Kelly Ayotte of New Hampshire and Mike Johanns of Nebraska and Democratic Sen. Ron Wyden of Oregon.

The growing of white potatoes is big business in Maine, the sixth-largest potato-producing state in the nation in 2010, according to the Maine Potato Board, based in Presque Isle. Maine farmers grow about 55,000 acres of white potatoes, selling $140 million worth in 2009, the board has said.

USDA officials say they are not bashing potatoes, but note that after studying the issue of improving the nutrition of food for federal nutrition assistance programs, the National Academy of Sciences’ Institute of Medicine recommended a focus on green, leafy vegetables, orange vegetables and whole grains.

The issue of potato consumption and nutrition gained attention earlier this year when a Harvard study found the potato to be a prime obesity culprit. French fries and potato chips were the worst uses of the potato, but even boiled potatoes contributed to weight gain, according to the study.

In proposing new food guidelines for those programs, which offer free and reduced-price meals to low-income children, the USDA wants to limit to one cup a week the amount of starchy vegetables – potatoes, peas and corn – that can be served as part of the school lunch program. It would ban the potato completely from the breakfast program.

The National Potato Council is lobbying vigorously against the new rule. It failed in a similar effort when the federal Women, Infants and Children program recently excluded the white potato as it added fruits and vegetables to WIC’s modest monthly food benefits package for low-income pregnant women, postpartum mothers and children 5 and younger. Indeed, the white potato was the only vegetable excluded from the WIC-approved fruits and vegetables list.

Collins and other potato proponents, including Snowe, maintain that the potato’s nutritional qualities – which include high levels of potassium – qualify it as a healthy vegetable under federal dietary guidelines. And, they say, potatoes are a low-cost food for schools with stretched budgets.

At an event in Washington earlier this month for school nutrition directors sponsored by the potato council, Collins said that she has been arguing for months to the USDA that potatoes meet USDA’s own general nutrition guidelines if they are prepared correctly.

“I don’t like taking the legislative route, which would be a funding restriction until they revamp the rule,” Collins said at the potato council event. “The overall goal of increasing fruits and vegetables is one that I wholeheartedly support. But this simply goes too far.”

But proponents of the federal rule limiting potatoes and other starchy vegetables say Collins and other pro-potato lawmakers voted in favor last year of the Healthy and Hunger Free Kids Act, and say that the potato is a starchy vegetable that federal dietary guidelines seek to limit. Proponents of the new rule limiting potatoes and other starchy vegetables in favor of dark green and orange leafy vegetables note that last year’s legislation authorizes sending more federal funding to schools to help pay for increased costs.

A White House fact sheet about the healthy and hunger free kids legislation released when President Obama signed the bill into law in December noted that it gives the USDA “the authority to set nutritional standards for all foods regularly sold in schools during the school day.”

In Maine, pediatric dentist Jonathan Shenkin of Augusta has picked up the campaign to uphold the USDA school lunch standards that limit potatoes in any form. Shenkin says Maine politicians are putting agriculture and corporate interests ahead of what’s best for the children eating school lunches and ahead of the need to attack the nation’s childhood obesity problem.

Shenkin has said that the Maine congressional delegation – Democratic Reps. Mike Michaud and Chellie Pingree also oppose the guidelines – are ignoring scientific evidence that starchy vegetable consumption leads to obesity and making “more of an economic decision.”

But at the potato council event in Washington attended by Collins, Doris Demers, the nutrition program director for York and Kittery schools, said the new rule limiting potatoes is “ridiculous.” Demers said that the day she was in Washington attending the potato council event, that three York and Kittery schools featured baked potato bars full of healthy topping choices such as chili, broccoli and beans.

MaineToday Media Washington Bureau Chief Jonathan Riskind can be contacted at 791-6280 or at: jriskind@mainetoday.com Twitter: Twitter.com/MaineTodayDC.