Quote Originally Posted by mikecash
This prompted a visit to the fridge......

Our current carton of Japanese milk indicates that it has been heated to 130 degrees for two seconds. It also says that it has been preserved according to the "ESL" method to extend the 賞味期限. It doesn't say what the "ESL" method is, and I don't have time to research it at the moment. I'm guessing that "ESL" may mean "Extended Shelf Life". The expiration date on this carton of milk is January 27th, and I doubt that it was bought more than a day or two ago.
Correct.

UHT (Ultra High Temperature)

UHT is a flash-heating-and-cooling sterilisation process that allows food to retain its nutritional value while preserving natural taste, colour and flavour. The right combination of temperature and time is what UHT is all about. No chemicals, preservatives, microwaves, or any type of radiation are ever used. UHT milk is heated to a temperature between 135 and 150 degrees Celsius for a minimum of one second.

UHT treatment is used to achieve food sterility. Combined with aseptic packaging, it delivers shelf stable conditions for food. Shelf stable products do not require refrigeration. This saves on transportation and storage costs. Natural resources are also saved by reducing green-house gas emissions.

There are many products that can benefit from UHT technology. Some examples: milk, cream, juice and soy-based products.

ESL (Extended Shelf Life)

ESL milk is quite different from well-known UHT milk. UHT milk is heated to a temperature between 135 and 150 degrees Celsius for a minimum of one second. ESL milk is only heated to a temperature between 85 and 127 degrees Celsius for a minimum of two seconds.

ESL milk can be stored for up to 21 days and it is as nourishing as pasteurised milk. But be careful, the longer shelf life is based on the package not being opened and that it is refrigerated.

Source : tetrapack site