Processing & Preservation
UHT Ultra-high temperature
Heating to roughly 135–150 °C for 2–5 seconds followed by aseptic packaging, giving a shelf-stable product without refrigeration.
What makes Tetra Pak milk shelf-stable for months without refrigeration until opened, unlike pasteurised milk which needs the fridge.
Related terms
Pasteurisation
Processing & PreservationA mild heat treatment that destroys vegetative pathogens and reduces spoilage organisms, without eliminating spores. Milk: LTLT 63 °C for 30 min, or HTST 72 °C for 15 s.
Aseptic packaging
Processing & PreservationFilling a commercially sterile product into a sterilised container in a sterile environment, sealing without further heat.
z-value
Food MicrobiologyThe temperature increase required to reduce the D-value by a factor of ten — the slope of the thermal death time curve.
HTST principle
Processing & PreservationThe principle that higher temperature for shorter time achieves the same microbial lethality with less loss of nutrients, colour and flavour.
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