Human consume other organisms and their constituents as food.All food organisms go through their own life cycles until harvested.The preharvest process comprises these feature in chronological order:genesis,growth,maturation,and reproduction.Various environmental factors affect the life process in whole or in part.These include ambient temperature,humidity,light,nutrients,composition of the atmosphere , and so forth. Failure to control the factors will affect the quality of food organisms and sometimes jeopardize their efficient distribution for human consumption.The same may be true for the postharvest process.