What is flash pasteurization?

What is the purpose of pasteurization?

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Flash pasteurization is a method of heat pasteurization of perishable beverages like fruit and vegetable juices, beer, and dairy products. Compared to other pasteurization processes, it maintains color and flavor better.

It is done prior to filling into containers in order to kill spoilage microorganisms, to make the products safer and extend their shelf life.

The liquid moves in a controlled, continuous flow while subjected to temperatures of 71.5 °C (160 °F) to 74 °C (165 °F), for about 15 to 30 seconds, a ratio expressed as pasteurization units.

The process is more prevalent in Europe and Asia than in North America.[citation needed]

Flash pasteurization is widely used for fruit juices. Tropicana has used flash pasteurization since the 1950s.[1] The juice company Odwalla switched from non-pasteurized to flash-pasteurized juices in 1996 after tainted unpasteurized apple juice containing E. coli O157:H7 sickened many children and killed one

There are actually several variations of milk pasteurization, but all involve the same basic principle. Briefly, milk is heated to a specific temperature for specified period of time.

The common methods of pasteruization are:

Low temperature/long time ("vat") pasteurization: 62.8 C (145F); 30 minutes
High temperature/short time: 71.7 C (161 F) 15 seconds

"Flash" pasteurization can be
89 C (192 F) 1 sec
90 C (194 F) 0.5 sec
94 C (201 F) 0.1 sec
96 C (204 F) 0.05 sec
100 C (212 F) 0.1 sec
96 C (204 F) 0.05 sec
100 C (212 F) 0.1 sec
UHT (ultra high temperature) milk is actually sterile (so it does not require refrigeration), and is heated to 138 C (280 F) for 2 sec
These are the minimum times required by law, and are generally slightly exceeded (for example, 167F for 18 seconds).

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