Final answer:
The batch method, also known as low-temperature long-time (LTLT) pasteurization, uses lower temperature for a longer period when compared to the flash or HTST method. It typically heats milk to 63 °C for about 30 minutes, while HTST involves heating to 72 °C for 15 seconds.
Step-by-step explanation:
The method of pasteurization which uses a lower temperature for a longer period of time is the batch method or low-temperature long-time (LTLT) pasteurization.
This contrasts with the flash method, which is better known as high-temperature short-time (HTST) pasteurization. While HTST pasteurization exposes milk to a temperature of 72 °C for about 15 seconds, the batch method typically heats milk to about 63 °C and maintains that temperature for around 30 minutes.
Both methods aim to reduce the number of spoilage-causing microbes and kill pathogens, but the batch method does so at a gentler pace and lower temperature.
Ultra-high-temperature (UHT) pasteurization, another process mentioned, heats milk to even higher temperatures, approximately 138 °C for 2 seconds or more, allowing the pasteurized milk to be stored for extended periods without refrigeration, albeit with possible minor alterations in taste and texture.
The choice between these methods of pasteurization depends on the desired shelf life of the product and the sensory qualities sought after by producers and consumers.