Friday, January 25, 2013

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.

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.

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. 


  1. If ESL treatment is in the range of 120 -140 deg C with holding time up to 4 secs, what is the difference between UHT treatment and ESL processing? The idea of ESL is to reduce products damage happens in the case of UHT treatment, retains fresh milk flavor and at the same time maintaining same or near shelf life of UHT treated products. Filling temperature in an aseptic m/c could be 20 -25 deg C, and no need to chill it to 4 deg C. Please comment!

  2. The definition of Extended Shelf Life (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. While the time/temperature relationships for ESL processing and UHT are similar, there are differences in the packaging and filling equipment, with much higher hygiene levels required for aseptically packaged (UHT) products. There is also a major difference in distribution, which has to be chilled in the case of ESL, but which can be at ambient temperatures for UHT/shelf stable products.

  3. Brian Shewell Sysco TorontoFebruary 20, 2013 at 7:42 AM

    ESL Dairy products,specifically fluid allow distributors like Sysco to partner with ESL processors nationwide to service Canada wide food service customers. Fluid milk/cream products in 250/500ml and 1 Ltr. formats dominate ESL availability, and ideally larger bulk formats could go extended life to allow consistency in shelf life and enduser flexibility in storage. One processor in particular has raised the benchmark and produces "Aseptic" packaged value added fluids in resealable containers. This format would be perfect for food service and retail users as frees up costly and limited cooler space as products can be stored or display at ambient temperature and chilled when needed. Canadian processors are slower than USA and European in utilizing "new" technology of Aseptic as extremely costly and with a Government Supply Managed system lack the desire with less competition pushing them to be leaders.

  4. In the UK, most ESL milk to be found in the dairy chill chain utilises the 'Cravendale' process, which uses micro filtration equipment. What both Arla and the major retailers, who use the process for their own label ESL product, fail to tell the public, who pay a significant premium verses normal HTST pasteurised milk is that the fat / cream will not go through the micro filtration process, and this constituent is actually sterilised to ensure the extended life. This process also accounts for the change in taste verses HTST treated product which somehow they have made a virtue of! The process is high capital and high operational cost and certainly not environmentally friendly. Other processes which are far lower capital and energy greedy, such as the MicroTek Purepulse MP3, which treats both the combined fat and non-fat milk constituents at ambient temperature and does not alter the taste, are being positively shunned by the UK top three milk producers, despite early trials indicating life of 6 weeks with no organoleptic change. One has to wonder why!?

  5. With regard to the processing of microfiltered milk, Peter Moore's comment that the fat/cream is sterilized separately from the whey as it would clog the pores of the filters, is correct. My experience with the taste of microfiltered milk, both from the UK and Canada, is that a low fat microfiltered milk will have a much fuller taste than one would expect. In other words, a 2% fat milk would have the taste approaching that of a full cream milk.

  6. Thank you for giving the information. I would like to suggest that eco-friendly packed materials should be used atleast for the packing of food.
    handheld packaging container company | handheld containers

  7. Dear All,
    Kindly with your good network advice how best we can be able to process and pack 60,000 liters per day

    Best Regards

    Josiah Mwangi

    +254 708474400