U can store in refrigerator under all aseptic condition & consume in next 6 hrs not beyond.

U can store the food in fridge and use it again after heating it properly

Complementary feeding is feeding started after 6 months. It's an add on to milk. But main thing is to introduce in step wise manner with fixed routine. Better to give home made food like curd rice, dal chawal, khichdi, raab, fruits but in paste or puree form. Avoid packet food or formula or Cerelac as they are not natural food items. Always good to give freshly prepared food items. Silicion made storage material are available for storing the food. But again reheating the same food makes change in taste, decrease the nutritive value and cause stomach infection. If we don't eat reuse, reheated food and don't like readymade items (like formula or Cerelac) why for the child.