Right to Know School Nutrition Act - Directs the Secretary of Agriculture make certain rules for institutions that serve irradiated foods as part of the school lunch program under the Richard B. Russell National School Lunch Act or the school breakfast program under the Child Nutrition Act of 1966. Requires institutions, prior to serving irradiated foods, to provide students and their parents or guardians with: (1) balanced information regarding such irradiation, including its purpose, nutritional effects, and potential adverse health consequences; and (2) the option of traditional, non-irradiated foods at every meal provided under such programs. Requires institutions to ensure: (1) clear labeling of menu items containing irradiated foods; (2) no commingling of irradiated and non-irradiated foods; and (3) prominent display of signs in school cafeterias indicating that irradiated food is being served.