The dairy industry is renowned for striving to preserve quality and safety while maintaining the freshness and taste of milk and dairy products for consumers.

An article in the Dairy Reporter (14 February 2023) shared the Journal of Dairy Science analysis on the impact on milk’s nutritional and sensory properties from containers the milk is stored in – glass, plastic (PET, HDPE, LLDPE) and paper-based.

Previously, the dairy industry focussed on containers that blocked out light to maintain freshness, but not much was known about how packaging influences flavour.

The properties of each container type play a distinct role in sensory and nutritional impacts – paper-based blocks out sunlight thereby reducing oxidation reactions, plastics have strong barrier qualities and are recyclable, and glass is known for its ability to retain flavour.

The analysis found package type does influence milk flavour and freshness:

  • Cartons and related paper-based packaging commonly used in school meal programs do not preserve milk freshness as well as glass and plastic.
  • Paper-based is susceptible to chemical transfer and was vulnerable to distinct refrigerator taint and/or stale flavour.
  • Cardboard was found to have a stronger ‘paper taste’ within hours of packaging.
  • Milk packaged in cartons and LLDPE have the highest intensity of off-flavours due to permeability and migrations between the material and the liquid.
  • Participants in consumer trials found differences between carton and glass, but not between PET and glass or HDPE and glass.
  • Chemical transfer was more apparent in cartons and plastic bags, having higher concentrations of packaging and refrigerator taint compared to LDPE, HDPE, PET and glass containers.
  • Skim milk is more susceptible to flavour impacts than whole milk.

Given cartons are the most prevalent packaging type for school kid meal programs in the USA, the authors noted that the consequences of using packaging that can contribute off-flavours may affect how young kids consider milk and how that may impact their consumption behaviour in the future.