What is the maximal shelf life of UHT milk?
Wikipedia says that the shelf life of UHT milk is "typically" between 6 and 9 months.
Does it mean that UHT milk always falls in this range? Is there UHT milk which has a longer or shorter shelf life? (I am not talking about ESL milk here, just UHT). What determines which milk has 6 months, which has 9 months, and which has more (if more is possible)? Is there a variation in the process used?
Best Answer
I'd never heard of ESL until your question, so I had to look that up. A local company did a lot of work developing UHT milk; I remember samples when they were first starting up production, and they were trying to find flavors additives which would mask the flavor change from the UHT processing. Since then a lot of companies have adopted the processing methods for other products, or just adopted the packaging. So, before I relied on any random box-packed product to be shelf stable, I'd check into how it was produced.
Proper UHT milk doesn't go bad until it's opened. It's sterile, and in a pretty sturdy container. Once opened, bacteria will get back into the container, and the milk will go bad as normal. When the local company started production of UHT milk, they were putting 2 year code dates on packages, and that was just the longest date the government would allow; I've had boxes 3-4 years old, which were fine.
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Quick Answer about "What is the maximal shelf life of UHT milk?"
Extended shelf life (ESL) milk has a shelf life of about 3 weeks under chill chain conditions and fills the gap between high-temperature short-time (HTST)-heated milk, which typically is assigned a shelf life of 10 days and ultra-high temperature (UHT)-heated milk, which can be stored for a few months without cooling ( ...How long does UHT milk last for?
UHT milk or long-life milk has a typical shelf life of six to nine months at ambient temperatures if unopened. Once opened, it should be refrigerated and used within seven days.What is the longest shelf life for milk?
UHT milk is a popular milk in many countries around the world. It can be kept \u201con the shelf\u201d for six to nine months without spoiling.Is UHT milk shelf stable?
The process for shelf-stable milk is called UHT pasteurization, or Ultra High Temperature. Milk is heated to a very high temperature for just a few seconds, which destroys bacteria for a longer shelf life.How does UHT milk last so long?
Long-life milk is heated to 140\xb0C for two seconds and then packaged aseptically. The increased temperature at which long-life milk is treated results in a greater reduction in bacteria and heat-resistant enzymes in comparison to milk that undergoes regular pasteurisation \u2013 giving it an extended shelf life.UHT MIlk 2 - How important is UHT shelf life
More answers regarding what is the maximal shelf life of UHT milk?
Answer 2
McGee's on Food and Cooking states that once opened
Pasteurized milk stored below 40°F/5°C should remain drinkable for 10 to 18 days.
It continues on the different types of pasteurization (bold mine)
There are three basic methods for pasteurizing milk. The simplest is batch pasteurization, in which [...] a few hundred gallons [of milk is heated at] 145°F/62°C for 30 to 35 minutes.
Industrial-scale operations use the high temperature, short-time (HTST) method, in which milk is pumped continuously through a heat exchanger and held at a minimum of 162°F/72°C for 15 seconds. [...]
The third method of pasteurizing milk is the ultra-high temperature (UHT) method, which involves heating milk at 265-300°F/130-150°C either instantaneously or for 1 to 3 seconds, and produces milk that, if packaged under strictly sterile conditions, can be stored for months without refrigeration. [...]
Sterilized milk has been heated at 230-250°F/110-121°C for 8 to 30 minutes; it [...] keeps indefinitely at room temperature.
I would assume that longer pasteurization (e.g. 3 seconds) and the higher temperatures (e.g. 150°C rather than 130°C) could add a few months before the milk starts to spoil.
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