Around the world, all roads lead to dairy. In Southeast Asia, increased urbanization is expected to result in healthier, higher quality food consumption, requiring producers to diversify their product portfolios. In the Americas, the U.S. Department of Agriculture just invested $20.2 million towards dairy innovation projects. Australia and New Zealand’s organic dairy products market is expected to hit $98.4 million in the next five years. The signs are clear: dairy is here to stay. In response, plants must be prepped to meet consumer’s demands.

Consumers want to believe in the quality of their products and extended shelf life is essential to safety and taste preservation. This is done using ultra-high temperature (UHT) processing. Heating the product to a high temperature (121ºC) kills harmful bacteria spores. To put it plainly, the higher the temperature and the longer time the product is kept at this temperature (holding time), the higher the bacteria spores ‘kill rate’, resulting in longer shelf life.

Although this equation is simple, the challenge dairy processors face is to balance this ‘kill rate’ with the preservation of desirable product characteristics, such as fresh taste and nutritional value. The key to effective UHT treatment is to find the right balance between optimal temperature and holding time. With thorough product testing, an effective UHT process can extend product longevity while retaining the quality, taste, texture and depth of the original product.

Different UHT technologies and processing parameters yield different results but having the correct controls in place is vital. For example, UHT processing can be achieved using direct or indirect heating. Which best suits your plant?

Indirect vs Direct Heating

Indirect heating solutions include tubular, plate and scraped surface heat exchangers. Tubular and plate are highly cost-effective solutions but, as the product is separated by the stainless-steel barrier in the heating medium, it’s more difficult to control the actual heating time. Due to this, indirect heating systems require a longer holding time (typically over 3 seconds) to reach the desired shelf life. This in turn effects taste.

Alternatively, direct heating infuses or injects steam directly into the product using infusion or injection technology. Injection UHT injects steam into the product to be treated through a specially designed nozzle before the product is cooled in a flash chamber. A more advanced option is our infusion technology which typically offers even more precise control with rapid and controlled heating of the product as it falls through the infusion vessel before being cooled in the flash chamber. For example, our InfusionPlus™ process can heat to 160°C and controls the holding time to less than a second. This extreme fast heating of the product enables a high level of vitamins to be retained in the product with minimum protein denaturation. This will result in a product with superior quality and taste whilst still ensuring the benefits of high thermal treatment.

Direct heating systems offer the most accurate temperature readings throughout the volume of the product. This vital control factor allows for shorter holding times, lessening the likelihood of overheating. This results in commercial sterility and extended shelf life while retaining a fresh-tasting product. Whatever the technology, quality is key.

Supply Chain

Once produced, dairy products must be transported to supermarket shelves. How this happens can also impact on the processing requirements. Products with a shorter shelf life need to reach the shelves quickly, requiring target markets be local to the production plant. The cold chain is another consideration. Markets with robust cold chains, as can be found in western Europe, assure suppliers a distribution processes at lower temperatures (5°C). In emerging markets, however, products often need to be created for storage at a higher temperature, around 10°C or even higher, for easier transportation. This requires a higher degree of bacteria spores ‘kill rate’.

The challenge for dairy processors is to balance product quality, price level and shelf life to achieve the ideal product for each specific market. With decades of experience in dairy processing and continuous research and development, SPX FLOW shares its processing expertise to help dairies choose the optimum technology for their specific needs. We are making advances that enable dairies throughout the world to create new and exciting products, open new market areas and generate new business opportunities. Check out our UHT series.