The branch of food science and technology that deals with the practical control of factors capable of adversely affecting the safety, nutritive value, appearance, texture, flavor, and keeping qualities of raw and processed foods. Since thousands of food products differing in physical, chemical, and biological properties can undergo deterioration from such diverse causes as microorganisms, natural food enzymes, insects and rodents, industrial contaminants, heat, cold, light, oxygen, moisture, dryness, and storage time, food preservation methods differ widely and are optimized for specific products. Apart from application of a single food preservation method, a combination of methods may be used to improve the safety and storage stability of foods. This concept is currently referred to as hurdle technology; it is also known as food preservation by combined methods, combination preservation, or combination techniques.