Infant Formula – Heat Treatment – APV Infusion Systems

Particularly regarding baby foods and infant formula milk, is leading to food manufacturers developing infant formulas to ensure they meet specifications of the highest standards in terms of bacteriological content, composition, and physical, chemical and functional properties. The challenge for manufacturers is to obtain a balance between high bacteriological quality without comprising the nutritional value.

The market for commercially prepared foods for infants and small children is already large and continues to grow, encompassing all the needs of the child from birth up until 3 years of age. For infants, breast milk or commercially prepared infant formulas are ideal. In fact, infant formulas are defined as mother’s milk replacers adapted to the composition of human milk. Infants have a lesser-developed immune system and are prone to allergies. As a result, only top quality ingredients should be used and high standards of hygiene should be maintained during production and packaging. The challenge is always to produce formula high in valuable nutrientswhile at the same time maintaining high bacteriological standards.

The core process for producing infant formulas comprises the unit operations of ingredient mixing, heat treatment - to obtain a product with a high bacteriological standard, and drying.

Heat Treatment

The main purpose of heat treatment during the production of infant formula is to create a product with a a small amount of viable bacteria and spores. The heat treatment can be something between a mild pasteurisation or a full sterilisation, depending upon product type and the stage in the manufacturing process. Selecting the right heat treatment depends on careful evaluation of the balance between high bacteriological standards and low destruction of valuable nutrients. Research has shown that excessive heat treatment should be avoided and that the following demands should be made on the heat treatment process: it should provide 1) fast heating, 2) short and precise holding times at maximum temperature, and 3) fast cooling.

The new Instant Infusion System Gold System (Type SIITM) from APV can help kill a high number of bacteria and spores while still keeping the nutritional value high and chemical changes low compared with other processes used for the manufacture of formula milk and milk concentrates.

SII uses advanced technology to hold the product for a fraction of a second at high temperatures before flash cooling. As this effective and gentle sterilisation strategy preserves vitamin content, nutritional content and product quality, it is the ideal solution for the high heat treatment of heat-sensitive products.

At the heart of SII is an infusion chamber. Using plate, tubular or scraped heat exchangers, product is preheated to between 55oC and 65oC before entering the top of the infusion chamber. Less than 0.2 seconds later, the product reaches the required UHT temperature of 140oC. A number of new techniques have been developed by APV to ensure that the product does not suffer from chemical damage, or burn onto the infusion chamber. For example, the lamination nozzle is cooled to avoid fouling and the design ensures that the product is dispersed in a circular pattern to avoid atomisation. Steam enters the chamber from its side, moving towards the centre via laminar flow, and condenses into the product without cavitations. This, in turn, prevents uncontrolled homogenisation. Eventually, the product comes into contact with the wall at the lower part of the infusion chamber, which is equipped with a cooling jacket. The thin film of condensate this generates on the inside of the chamber eliminates product fouling.

Temperature control in the chamber is crucial and is carried out via steam pressure control. A temperature sensor mounted in the product holding pump housing is used to monitor actual sterilisation temperature and will ramp the steam pressure controller if necessary. This fine control of sterilisation temperature prevents the partial overheating of product constituents that can be an issue with injection and SSHE technologies. Next comes the rotary holding pump where an APV-patented design ensures product is held for under 0.5 seconds. This extremely short period is possible because the holding is only the time the product is inside the pump. To control the temperature during the short holding time a thin piece of gold is wrapped around the temperature transmitter. As gold is 20 times more heat conductive than stainless steel, the temperature can be measured much more quickly and maintained accurately. The last step in SII is the vacuum chamber, from which steam is removed to a condenser. Product is pumped directly from here to a spray dryer or plate/tubular/scraped surface heat exchanger section for final cooling.

The result is a process that brings a huge number of benefits over other technologies currently in the marketplace, including uniform bacterial kill rate for medium and high viscosity products, consistent product quality, less fouling and proven long operating times. SII technology can handle product capacities from 100-12000 l/h, a maximum viscosity at sterilisation temperature of 500cp and maximum total solids of 60 percent. So it is no surprise that manufacturers of infant formula milk and milk concentrates in locations as diverse as the Czech Republic, China, Vietnam, Denmark, Germany, Switzerland and the UK are committed to using the new process.

About APV

APV is a world leader of high quality process technologies and engineering solutions for the dairy, food, beverage, brewing, pharmaceutical and healthcare industries. As a subsidiary of Invensys plc, APV has access through its sister companies to some of the latest and most innovative automation systems. From engineered components through to complete, fully automated process plants, the company focuses on adding value to its customers’ business performance and profitability. APV’s range of manufactured products includes heat exchangers, homogenisers, pumps and valves for hygienic applications.

APV's services extend far beyond the product itself. From manufacturing the equipment to offering our customers an extensive, global network of after-sales parts and services, APV ensures that the equipment performs to optimum efficiency throughout its lifetime.

APV solutions are supplied through its global network of sales and service offices located in more than 40 countries throughout the world.

About Invensys

Invensys is a global automation, control and process solutions group. Its products, service expertise and ongoing support enable intelligent systems to monitor and control processes in many different environments. Leading companies in a wide range of industries rely on Invensys to help them perform with greater efficiency, safety and cost-effectiveness.

The Invensys Group comprises five businesses: Process Systems, APV, Eurotherm, Rail Systems and Controls. The Group is headquartered in London, employs more than 30,000 employees in 60 countries, and is listed on the London Stock Exchange.

Contact details:

Joanne Gibbs – Global Marketing Communications Manager
Siva Subramaniam – Asia Pacific Marketing Manager
Peder Baekgaard – Global Dairy Technical Director

APV: www.apv.com