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How does ultra-high-temperature pasteurization extend milk’s shelf life?
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Louis Pasteur
In the 19th century Louis Pasteur's work established the germ theory of disease, proving that microorganisms cause fermentation and sickness, which led to the development of pasteurization, aseptic techniques in medicine, and effective vaccines for diseases such as rabies. (Painting by Albert Edelfelt, 1885.)
Ultra-high-temperature (UHT) pasteurization extends the shelf life of milk by heating it to 138–150 °C (280–302 °F) for one or two seconds. This intense heat treatment destroys microorganisms that cause spoilage and potential pathogens.123
To achieve a long shelf life, the milk is then aseptically placed into sterile, hermetically sealed containers, such as metal cans or five-layer laminated boxes. Because this process and the specialized packaging prevent recontamination, the product can be stored without refrigeration for six to nine months. While this method is highly effective for preservation, it is noted that the flavor of UHT-treated milk may not taste as fresh as milk processed through conventional methods.231