Commercial shelf life for frozen vegetables is typically stated in the range of
eighteen to twenty-four months at minus eighteen degrees Celsius or colder, but the
number on a specification is a claim the supplier has to justify, not a property of the
category.
The justification is a stability study. Because the product sits below the temperature
at which microbial growth occurs, shelf life here is a quality question rather than a
safety one: sensory attributes, colour and texture assessed over the claimed period, at
the claimed temperature, in the pack that will actually be used. A shelf life
demonstrated in one film does not transfer to a thinner one.
Three things shorten it in practice. Storage warmer than the claimed temperature, which
accelerates every degradation reaction. Temperature cycling, which causes moisture
migration, recrystallisation into larger ice crystals and freezer burn at the product
surface. And a pack with poor moisture barrier properties, which loses water to the
freezer atmosphere however stable the temperature is.
For a buyer, the clause that matters as much as the total shelf life is the residual
shelf life required on delivery – the proportion or the number of months that must
remain when the goods arrive. Specify it, and specify what happens when a delivery
arrives short. Residual shelf life is one of the most common reasons a technically
conforming delivery is refused.