 Food preservation, food preservation prevents the growth of microorganisms such as yeasts or other microorganisms. Although some methods work by introducing benign bacteria or fungi to the food as well as slowing the oxidation of fats that cause sensitivity. 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. 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. Not sugaring to prevent the regrowth 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. 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. Maintaining or creating nutritional value, texture and flavor is an important aspect of food preservation.