Chemical preservation of perishable foods by various additives or preservatives is a significant part of the food preservation industry which is used in combination with other forms of preservation like freezing, canning, dehydration etc. Chemically preserved food products like squashes and crushes etc. can be kept for a fairly long time even after opening the seal of the bottle. It is however essential that the use of chemicals is properly controlled as their indiscriminate use is likely to be harmful. These should be added in very low quantities so that organoleptic and physico-chemical properties of the foods are not altered at all or only a little.