<P> Food preservation is to prevent the growth of microorganisms (such as yeasts), or other micro-organisms (although some methods work by introducing benign bacteria or fungi to the food), as well as slowing the oxidation of fats that cause rancidity . Food preservation may also include processes that inhibit visual deterioration, such as the enzymatic browning reaction in apples after they are cut during food preparation . </P> <P> Many processes designed to preserve food involve more than one food preservation method . Preserving fruit by turning it into jam, for example, involves boiling (to reduce the fruit's moisture content and to kill bacteria, etc .), sugaring (to prevent their re-growth) and sealing within an airtight jar (to prevent recontamination). Some traditional methods of preserving food have been shown to have a lower energy input and carbon footprint, when compared to modern methods . </P> <P> Some methods of food preservation are known to create carcinogens . In 2015, the International Agency for Research on Cancer of the World Health Organization classified processed meat, i.e. meat that has undergone salting, curing, fermenting, and smoking, as "carcinogenic to humans". </P> <P> Maintaining or creating nutritional value, texture and flavor is an important aspect of food preservation . </P>

Which one of the following substance is used for preservation of food grains