ESL milk, ESL (extended shelf life) milk is labelled as ‘longer-lasting’, but just like regular fresh milk, it must be stored in the chiller or in the fridge.

As its name suggests, the ‘longer-lasting’ milk does not spoil as quickly as fresh milk. Whereas traditional fresh milk can be stored unopened in the fridge for six to twelve days, an unopened bottle or carton of ESL milk stored in the fridge (maximum 8 °C) will keep for 21 to 30 days. UHT milk, by contrast, can be stored at room temperature for up to 12 weeks. In terms of shelf life, ESL milk is therefore positioned between traditional fresh milk and UHT milk.

ESL milk production methods

ESL milk can be produced in various ways, though there are no statutory regulations governing its production. The following methods are currently used to manufacture ESL milk:

1. Indirect heating using tubes or plates

2. Direct heating through steam injection/steam infusion

3. Membrane process (microfiltration)

4. Depth filtration

5. Bacteria removal separators

Important note

The method a manufacturer adopts to maintain the sensory quality of its milk is more a matter of cost than the quality of the end product.

It is important to note that, irrespective of the method used to produce ESL milk, the manufacture of this dairy product is only possible if it is seen as an integrated, contiguous process, and as a value chain spanning from the dairy farmer to the consumer, via the dairy and the retailer. As such, the process must be organized and implemented in a systematic fashion. For instance, the hygiene and quality of the raw material starts in the cow stall, a seamless refrigeration chain must be maintained from the milking stage onwards, and the packaging and the standard of processing equipment (standard, clean, ultra-clean, aseptic) must be fine-tuned to achieve the target product quality, i.e., the target shelf life.