Somehow Congress can find money to give tax breaks to billionaires. But in a little-noted provision of its reauthorization of child nutrition programs, signed into law today by President Barack Obama as part of the Healthy, Hunger-Free Kids Act, lawmakers have told schools to raise lunch prices to at least cover what it views as the full cost of making a meal. Entitled “equity in school lunch pricing,” the new mandate could, by increasing prices gradually for students whose families aren’t low income, pump an additional $2.6 billion into the school meal program over the next 10 years, according to one estimate.

While that’s a much-needed infusion of cash, school food services professionals say the move could have the side effect of driving hundreds of thousands of children from the federally subsidized school meals program. The School Nutrition Association (SNA), representing some 50,000 food service workers across the country, likens the new law to cuts in federal support for school meals enacted during the Reagan years, when participation in the National School Lunch Program plummeted 25 percent among full-price students because schools were forced to charge more — and ketchup was declared a vegetable.

“When you raise prices, it has a real impact on participation,” said SNA spokeswoman Diane Pratt-Heavner. “Our members tell us time and time again, even when they raise prices by just a dime, they see participation drop.”

“The downside of raising meal prices during these tough economic times is that you run the risk of making the meals unaffordable for kids whose families just barely miss the financial eligibility cut-off,” said Kate Adamick, a school-food consultant who has long complained about the pricing disparity. “This is a significant reality in lower-middle class communities, especially for schools located in parts of the country in which the cost of living is extremely high, such as New York City and San Francisco, to name just two. I think this is the right change that may be coming at the wrong time.”