Dairy technology is a division of engineering that deals with the processing of milk and its products. Dairy technology study involves processing, storage, packaging, distribution and transportation of dairy products by implying the science of bacteriology, nutrition and biochemistry. Dairy plants process the raw milk they receive from farmers so as to extend its marketable life. Two main types of processes are employed: heat treatment to ensure the safety of milk for human consumption and to lengthen its shelf-life, and dehydrating dairy products such as butter, hard cheese and milk powders so that they can be stored.