Mid-afternoon break: Ultrahigh temperature processing and milk

There’s a lot more to milk then just what’s floating your breakfast cereal.

We’re not talking facts such as milk coming from cows but rather how milk can stay shelf stable for so long. People don’t want to buy milk and have to throw it away the next day. So how, does milk stay good for so long on the shelf?

One of the most common methods for extending shelf life is through pasteurization, which kills pathogens and spoilage organisms. However, a tiny number of microorganisms can continue to live after pasteurization. These organisms are slow growing and held at bay by refrigeration. However, producers also may hit their products with a second line of defense against microorganisms via either in-container sterilization or ultrahigh temperature (UHT) processing.

The processes behind shelf-stable milk were highlighted in a recent article in New Food magazine.

It’s an interesting read. Here are some of the highlights:

  • In-container sterilization occurs when the final containers of milk are heated at 110-120°C for 10-20 minutes. UHT processing occurs when milk is heated in a “continuous flow system at 140°C” for about five seconds. Both methods kill off remaining microorganisms that stick around after pasteurization. However, they have different chemical effects on the milk, such as taste differences and color.
  • UHT milk often has a “cooked” flavor as compared to pasteurized-only milk.
  • UHT processing may reduce how allergenic proteins in milk are as a result of the milk being exposed to high temperatures.

To read the full article, click here (subscription required).

To view some of Neogen’s testing products for UHT processes, click here.

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