"Most foods are subjected to a heat treatment—in the household kitchen or during industrial premanufacturing. This treatment has at least two functions. First, it makes nutrients more accessible for digestion; however, this aspect is not a subject of this review. Second, it aids in the preservation of foods, which must be stored for prolonged periods after harvest or slaughtering. The thermal treatment reduces the bacterial load and diminishes enzymatic activity, which otherwise can lead to rapid spoilage of raw food materials or the foods prepared from them. This aspect of preservation is growing ever more important as the trend of population movement to large urban centers increases the distance between the producer and the consumer, and the time between harvest and consumption."