- QC centers must meet the following criteria to be included: (1) have > 30 children ages 2-5 enrolled; (2) Serve low income families; (3) be a part of the USDA food program and Supplemental Nutrition Assistance Program (SNAP) eligible; (3) Reflect the ethnic diversity of the MDC Public School System (63 percent Hispanic, 19 percent African American, 18 percent white); and (4) Center directors agree to participate and sign a letter of commitment (see Documents of Collaboration).