Food security is a condition related to the ongoing availability of food. Concerns over food security have existed throughout history. There is evidence of granaries being in use over 10,000 years ago, with central authorities in civilizations including Ancient China and Ancient Egypt being known to release food from storage in times of famine. Yet it was only at the 1974 World Food Conference that the term 'food security' was established as a formal concept. Originally, food security was understood to apply at the national level, with a state being food secure when there was sufficient food to "sustain a steady expansion of food consumption and to offset fluctuations in production and prices". A new definition emerged at 1996 World Food Summit; this time with the emphasis being on individuals enjoying food security, rather than the nation. According to the Food and Agriculture Organization (FAO), food security "exists when all people, at all times, have physical and economic access to sufficient, safe and nutritious food to meet their dietary needs and food preferences for an active and healthy life"