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How does batch pasteurization differ from continuous-flow pasteurization?

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Learn about food preservation and the various methods to preserve foodstuffs — food preservation An overview of food preservation.

Batch and continuous-flow pasteurization differ primarily in their operational scale, equipment, and processing time-temperature profiles.

Batch (Vat) Pasteurization

Also known as the low-temperature–long-time (LTLT) process, this method involves heating food in large, double-jacketed vats. It is typically used in smaller processing units with yields of less than 1,000 liters per hour. A common standard for milk is heating to 63 °C (145 °F) for 30 minutes.1

Continuous-Flow Pasteurization

This method is designed for large-scale commercial operations, often processing more than 5,000 liters per hour. It utilizes plate-type heat exchangers to move liquid continuously through a system of thin metal plates for rapid heating and cooling.12

Common variations include:
* High-Temperature–Short-Time (HTST): Typically heats milk to 72 °C (162 °F) for 15 seconds, followed by rapid cooling.12
* Higher-Heat–Shorter-Time (HHST) and Ultrahigh-Temperature (UHT): These involve even higher temperatures for very brief durations, allowing for significantly extended shelf life.1

HTST treatments are generally preferred over LTLT because the rapid processing causes less damage to the nutritional and sensory characteristics of the food.2