Even a few extra days of shelf life for chilled milk can be a significant benefit to dairy companies, allowing them to consolidate operations and extend their distribution chain, reports Ahmed ElAmin.
Extending the shelf life beyond that - by 30 or even 90 days - opens up new opportunities for marketing milk products to consumers demanding quality and safety, said Gail Barnes, Tetra Pak'sbusiness development manager for the company's chilled carton operations in North America.
Extended shelf life (ESL) is an imprecise umbrella term referring to solutions that extend the shelf life of dairy and other chilled products beyond the pasteurised level.
In the UK premium microfiltered ESL milk has captured 11 per cent of the market. In the past 12 months volume share has increased by 29 per cent, while the value of sales has increased by 34 percent. The product has a 23-day shelf life. Meanwhile in the US the market for ESL products is growing at about 20 per cent a year, driven by the soy and organic milk markets, Barnes said.
Extended shelf life (ESL) processing and packaging systems are being used in the production of white and flavoured milk, fortified, enriched and fermented products, cream, dairy desserts, soydrinks and iced tea and coffee.
Tetra Pak's new marketing strategy, called 3SL, marks an attempt by the company to increase co-operation among Tetra Pak's units, Barnes said in an interview with FoodProductionDaily.com. The aimis to provide a full system along the entire processing chain, from the time the milk enters the plant to when product is put on transport trucks.
In addition to providing the equipment, Tetra Pak will also provide advice on plant hygiene and operation.
"The key to ESL technology is hygiene," Barnes said. "The shelf life of a chilled dairy product cannot be extended without first raising the levels of hygiene across thewhole dairy. No single piece of equipment will do the trick. ESL is a system, that's success depends on the hygienic strength of the entire production, packaging and distribution chain."
The technology for extending the shelf life of products is used to increase microbial reduction during processing, avoid re-contamination during filling and maintain a reduced distributiontemperature.
Ultra-pasteurisation and microfiltration are the two major processing technologies dairy companies use for extending the shelf life of chilled dairy products. Producers can also use bactofugationtechnology to gain a few days of additional shelf life.
Ultra-pasteurisation is a high heat treatment process. Microfiltration process is always linked to a pasteurisation process and is currently only used to process white milk products. Bactofugationis always combined with a thermal process and can be linked to existing pasteurisation equipment.
Filling machines used for ESL applications must be equipped to disinfect and sterilise the surfaces, air and packaging material that come into direct contact with the product. Package disinfectionin current ESL filling technology is normally achieved by the combined use of hydrogen peroxide and UV light.
Packaging materials vary depending on the filled product and target shelf life. All milk products require a light barrier material for protection against nutritional and sensory quality degradation. For most white milk products, no special oxygen barrier material is needed, Barnes said.
"Because of the complex nature of ESL, there is no standard ESL processing and packaging solution," Barnes said. "Optimal line solutions have to be developed to suitindividual needs and the strengths and weaknesses of whole production and distribution chains."
Using ESL technology extended the shelf life of Hansa-Milch's "Maxi Frische" brand to 25 days, allowing the company to increase its distribution area by 50 per cent, Barnes said. Thecompany also gained by having fewer production runs and lower spoilage rates. Returns rates also fell.
In the US WestFarm Foods used ESL equipment from Tetra Pak and others to extend the average maximum distribution range for pasteurised products from each of its plants from 160km to customers inthe western US, Hawaii and Alaska. WestFarm is now attempting to find a market in Hong Kong, according to the company.
Tetra Pak currently markets Tetra Centri, Tetra Alcross and Tetra Therm Aseptic VTIS as three processing systems that can be used for ESL products. The company's three complementary filling and packagingsystems are Tetra Top, Tetra Rex and Tetra Brik.