on-site school meal preparation system
Refers to a system where school lunches are cooked in the school's own kitchen, as opposed to being prepared at a central facility and delivered.
In this area, many schools provide school lunches using the on-site preparation system.
センター方式 is the contrasting system where meals are cooked at a central kitchen and distributed to multiple schools, while 自校方式 means each school prepares its own meals.
Compound of 自校 (one's own school) and 方式 (method, system).