MINNEAPOLIS (AP) - Programs aimed at getting school children to eat locally grown food have exploded in popularity.

U.S. Deputy Agriculture Secretary Kathleen Merrigan says the programs have spread so quickly her agency doesn't have up-to-date figures on how many schools are serving students local vegetables, fruits and meat. But one nonprofit estimates there are over 2,500 programs involving more than 10,000 schools in all 50 states.

Merrigan used the School Nutrition Association convention in Nashville, Tenn., to release a report Tuesday highlighting what works in farm-to-school programs, what doesn't, and what the government can do to help them work better.

She also announced a pilot program that will give Michigan and Florida schools more flexibility to use federal school lunch money to buy local food, with hopes the program can be expanded nationwide.