Extended Shelf Life - The Future For Chilled Dairy?

Dairies from Tokyo to Toronto, Beijing to Berlin are examining the opportunities created by Extended Shelf Life (ESL) technology, while new processing, filling and packaging systems are being developed and launched. Behind this technological drive are strong commercial arguments. Even a few extra days of shelf life can be a significant benefit to the producer, the retailer, and the consumer. Further days beyond that - up into the spectrum of an extra 30 or even 90 days - opens up new and unique horizons for the marketing of milk and other dairy products.

The definition of ESL differs depending on geography and which products are being processed. In the USA, the objective is to use ESL technology to maximize the shelf life of ‘white’ and value added chilled milk products to between six and nine weeks, under storage below 6°C. The ESL processing treatment used to achieve this longer shelf life is a high heat treatment, and benefits include larger marketing and distribution areas and more efficient production and distribution.

Hygiene

The key to ESL technology is hygiene. The shelf life of a chilled dairy product cannot be extended without first raising the levels of hygiene across the whole dairy. New processing and filling/packaging offers good opportunities for lifting the hygiene level in most dairies. However no single piece of equipment will do the trick. ESL is not just about technology and equipment, it is about a system, the success of which is dependent on the hygienic strength of the entire production and distribution chain. 

Starting off with the same quality of raw  milk, it can be seen that ESL processing technology reduces the microbial load by a much greater degree than regular pasteurisation. Then, due to the superior hygienic design, ESL filling technology provides a much greater degree of protection against re-contamination from the filling environment. Thus in effect, the quality of the product fed to the filler is largely maintained without re-contamination. The combined effect of the processing and filling, results in the ESL product having a reduced microbial load compared with a regular pasteurised product - which will be spoiled in shorter time, due to this load. Broadly, this means that an ESL product will tend to be safer and of superior quality than a pasteurised product, as a result of having been produced in a more hygienic and tightly controlled environment. 

Food safety

ESL technology offers advantages in terms of both product safety and product quality. The basis for this is improved hygiene and the reduction of the risk of re-contamination by pathogenic and spoilage organisms during production and distribution. 

Efficient production

Globally, consolidation within the dairy industry has led to fewer and larger plants, distributing over wider geographic areas. ESL technology allows dairies and other manufacturers to exploit the economies of scale that result from such consolidation. Indeed, exploitation of economies of scale has become the key to growth and even survival for many producers in the dairy industry. Longer runs translate into less product wastage during changeovers while the improved hygiene and longer shelf life that ESL technology offers result in fewer returns for the dairies and considerable cost savings.

Wider distribution

ESL technology allows wider distribution of chilled products, allowing for national distribution in major dairy markets such as the USA, pan-European distribution in Europe, or export to other regions.

Value Adding

ESL technology allows entry into higher margin  "Value Added" product sectors within the dairy industry. Examples of higher margin value added products include flavored milks and active functional dairy products.

Ultra-Pasteurisation

High heat treatment or ultra-pasteurisation, the dominant ESL technology used in North America, offers good processing flexibility when it comes to product quality and shelf life range. Direct heat treatment is commonly used due to what is perceived to be better sensory quality. Processing temperatures range typically from 120°C/248F up to around 140°C/284F, with holding times between 0.5 and 4 seconds.

Shelf life potential

The shelf life potential with ultra-pasteurisation is influenced by both environmental and operational factors. At a distribution temperature of 4C/40F, a shelf life of 30 - 90 days is possible, depending on the type of product. To leverage the full shelf life potential of this type of processing, re-contamination must be minimized, e.g. ESL fillers (including filler sterilization and packaging material disinfect ion) must be used and package integrity and stability must be maintained. A gas and light barrier in the packaging material would also be required. 

Non-thermal processing technologies

While the dairy industry under current high temperature/ultra-pasteurisation conditions and sanitary standards achieves a safe product with excellent quality, combining non-thermal technologies such as UV illumination with pasteurization, could achieve a similar level of quality and safety, but with a smaller carbon footprint as a result of less energy used for processing. 

The future for chilled products?

The global trend towards dairy industry deregulation has created a competitive market situation for local dairies as well as for multinationals. Consolidation and exploiting the economies of scale have become the key to growth and even survival for many dairies. 

In this new scenario, ESL technology is a key tool to ensure that the milk can travel the greater distances required by wider distribution areas, while remaining fresh and having the required shelf life after arrival at its destination. In a generally highly commoditized and low profit industry, ESL technology also allows entry into and leveraging of highly profitable, value added segments. 

With the current focus on food safety issues in the food industry, and with the recent well-documented food scares and consumer food poisoning incidents, product safety is fast becoming the major driver for ESL technology in many markets.