Indirect UHT processing suitable for Africa

At the recent South African Society for Dairy Technology symposium held in Bloemfontein, Uwe Schwenzow from Tuchenhagen Dairy Systems in Germany visited South Africa and gave a presentation on UHT product possibilities.
Schwenzow, employed for 19 years at Tuchenhagen Dairy Systems (previously known as Finnah), is its engineer responsible for research and development, and is involved in sales and projects.
Finnah, which has been supplying the SA market for 20 years, was acquired by GEA Tuchenhagen in 1989. Its UHT technology has been developed considerably since then.
Says Schwenzow: "UHT (Ultra High Temperature) processing plants are ‘the answer' for producers in South Africa and other African countries. That became more clear to me the more I learned at the symposium."
Why should UHT be of interest for Africa?
Because of the long distances which dairy products in Africa must be transported, but also because of the high temperatures which are normal here. Such temperatures would normally require an unbroken cold chain, but for an aseptic product an ambient supply chain is more convenient and more practical, which can only be made possible by the UHT process.
Tuchenhagen Dairy Systems is part of the GEA group and delivers total, prefabricated modular plants with minimised erection costs. The plants are custom-made and designed as optimised solutions. "We begin by asking the client what (s)he wants to produce – for instance the type of product – and the shelf life required. We design the plant together with the customer," says Schwenzow.
Why indirect heat processing for a UHT?
Tuchenhagen supplies UHT plants with both direct and indirect heating systems but strongly recommends indirect heating systems, primarily because of lower costs but still with good product quality. Indirect heat processing methods are the best way to achieve an efficient, reasonable and reliable UHT treatment, says Schwenzow.
However, to date, aseptic treatment systems in Africa have largely used direct heating.
Companies installing new UHT plants should ask their potential suppliers more questions, and in particularly get comparative estimates of the technical properties of those UHT plants, says Schwenzow. "Ask more searching questions than simply about the product technology and what the initial costs of the UHT plant are – questions like how much energy it will use, how much energy it will re-use, and what its running costs will be."
Of course the largest single cost is always the raw material (normally milk), but considerable savings can be made on the fraction of costs involved in processing. The following savings for indirect versus direct heating are estimated:

  •  20 – 30% lower fixed capital costs.
  • 40 – 50% lower total ongoing variable costs for maintenance, utilities and energy (steam, electricity, water). For example, with the indirect process 85-90% of the energy is re-used, compared to only 50-60% with direct-heat processing.

Furthermore, the indirect process is simple and reliable, with fewer parts and valves than the direct process. For example, in the indirect process only one control loop is required, against at least four loops normally required with a direct heating system. An indirect UHT plant does also not require steam of foodgrade quality or an aseptic homogeniser.
The specific design of the highly efficient tubular heat exchanger makes visual inspection using simple gaskets possible. The tubular heat exchanger of Tuchenhagen guarantees a safe sterilisation before the production, a long running period with safe and good product treatment, and efficient CIP.
The Tuchenhagen indirect UHT plants can offer much more product flexibility. Production can be more easily switched between different products with similar viscosities – for instance milk and juice.
Originally UHT was only for milk, but today UHT product possibilities encompass all sorts of milk, cream, custard, desserts, ice cream mix, condensed milk, non-dairy creamer, juice, drinks with fibres and pulps, food concentrate, vegetable drinks, soy products, egg products, sauces, ketchups, mayonnaise, pharmaceutical products, water, etc.
Another major advantage of the Tuchenhagen UHT plants is the ability to process milk with a poorer quality. This was for instance the case at a recent installation of a refurbished UHT plant in Sudan, where although the raw material is of poor quality, the indirect UHT system can treat considerable amounts of milk before cleaning is necessary. The milk can be processed as raw milk without an energy- and time-consuming extra heat treatment and standardisation process as normally used – due to an integrated Westfalia separator and a protein stabilising heat treatment section. This is also the case for a new turnkey UHT plant for southern Africa which is being installed currently.
In UHT products, the use of cartons of different shapes and multi-layered PET bottles (not yet seen in Africa, but becoming increasingly popular in Europe) makes UHT products easily transportable and gives good quality shelf life. Alternatively, smaller volumes are possible in aseptic sachets or pouches, and larger volumes in the bag-in-box units. Without refrigeration the products are safe for consumers for at least three months – with no risk of re-infection until they are opened.
Following the recent GEA acquisition of the Italian company Procomac, a leading supplier of technology for filling of aseptic multi-layered PET bottles in the UHT process, Tuchenhagen can now offer total turnkey solutions in this respect.
Internationally Tuchenhagen Dairy Systems has installed about 60 custom-made UHT systems in the past two years.

For more information, please contact Tuchenhagen's SA Sales Manager for Dairy, Food & Juice in South Africa, Stig Thorslund: Cell phone +27 82 922 2434; ;