Food Security is a condition where food is at a risk, where people do not have access to food! When people do not have access to food it is taken in terms of food security. Many countries like China and Egypt in early ages have central authorities that deal with all issues related to food.
It was in 1970s when food security was defined in terms of adequate supply of food to sustain a steady expansion of all food stuff,later definitions included access and demands,in 1960s standard definition of food security was when all people have physical access to safe,sufficient,nutritious food to meet their daily intake.
Another term is household food security where every house is having a sufficient food supply or not,around the world it is in Africa where more infants and children loose their life due to food insecurity,a term that defines limited or uncertain ability to acquire basic food amount.
Food security has four pillars identified as: availability ,access, utilization and stability by FAO.