Which hygiene concepts with dead-space-free design and smooth surfaces are state of the art for milk powder applications?
In milk powder applications, hygienic design is regarded today as the state of the art. Plants are designed so that product residues cannot accumulate as far as possible, can be removed easily and give rise to no unnecessary contamination risks. In practice this means above all dead-space-free, self-emptying geometries, low-crevice connections and smooth, readily cleanable surfaces. Milk powder is particularly demanding, since even slight residual moisture, residues or areas that are difficult to access can markedly increase the risk of microbiological contamination.
Dead-space-free construction
Product-contact components are designed so that powder cannot settle in cavities, threads, behind seals or in structural corners. Vessels, hoppers and pipework are given suitable inclinations, radii and outlets so that product and cleaning media drain completely and no residual material accumulates. Transitions are executed with few or no crevices; welds, flanges and sealing points are smooth, fully welded through and re-worked, so that no interstices that are difficult to clean arise. Threads, screw heads or dead spaces on fittings and sensors are either avoided or encapsulated in a hygienic manner, in order to prevent dust nests and the formation of biofilm.
Smooth and robust surfaces
For product-contact stainless steel surfaces in milk powder production, roughness values of Ra ≤ 0.8 µm are usually required; in particularly critical areas Ra ≤ 0.4 µm or electropolished surfaces are used. Smooth, corrosion-resistant surfaces reduce the build-up of powder particles and facilitate dry cleaning as well as wet cleaning where applicable. Typical materials are austenitic stainless steels such as 1.4404/AISI 316L with a passivated surface, combined with high-grade, smoothly ground welds free of pores and heat tint. Product-contact seals, plastics and elastomers must be suitable for food use and must not release any substances into the milk powder.
Cleaning and zoning concept
In many milk powder plants, dry cleaning with extraction, brushes or compressed air takes priority, since water can create undesirable microbiological risks. Where CIP or wet cleaning is required, these areas are clearly separated from dry-operated zones; hygienic process connections and CIP systems are of dead-space-free, EHEDG-certified design. A division into hygiene zones and airlocks, together with matching pressure and material flow concepts, helps to avoid cross-contamination. The design must be laid out so that cleanability and inspection options are validatable and can be documented traceably in the course of audits.
How amixon® implements dead-space-free construction and hygienic design
Freedom from dead space as a design principle
- In amixon® precision mixers (among others VM, HM, AM, KoneSlid®, SpherHelics® and Gyraton®), the mixing chamber and mixing tool are welded and ground free of joints. There are no crevices, bolted connections or capillary gaps in the product-contact area. The mixing tool is mounted and driven exclusively from above, so that the lower shaft passage, which is classically critical for contamination, is dispensed with entirely.
- The standard connection with discharge flap closes flush and dead-space-free with the inner wall of the mixing chamber. Dead-space-free ball segment valves are available as an alternative. The large inspection doors are manufactured by the Clever-Cut® process and seal permanently dead-space-free with the OmgaSeal® door seal. A vacuum-tight or pressure-tight design is also available on request.
Cleaning: wet and dry, validatable
Programmable target-jet washing lances make wet cleaning of the mixing chamber possible. The SinConcave®/SinConvex® mixing tool supports complete drainage of product and cleaning medium. The mixers are designed for dry and wet cleaning regimes. Changing between the three cleaning regimes DRY, DAMP and WET is provided for in the design.
Certified standards
on request, amixon® mixers meet the EHEDG guidelines, the FDA hygiene guidelines, the design specifications of the 3-A Sanitary Standards and GMP requirements, and can be used FDA-compliantly as sterile mixers and reactors.
In the production of dairy products and infant formula, amixon® mixers are in use worldwide at manufacturers and contract manufacturers: vitamins, minerals, trace elements, encapsulated omega-3 fatty acids and probiotics are mixed in homogeneously and gently downstream of the spray tower, without agglomerates being destroyed.
Manufacture in Paderborn as the quality foundation
amixon® develops and manufactures exclusively at the Paderborn works – with the greatest depth of fabrication and all components from Germany. As a certified welding company with European, Japanese, Korean and American qualifications, amixon® designs every apparatus as a one-off on the basis of the operator's URS. Quality control remains entirely in-house and every specification is verifiable down to component level. This manufacturing sovereignty also secures long-term supply. Every component can still be reproduced decades later.
Verification in the amixon® pilot plant
amixon® checks in advance in the pilot plant whether the specific formulation delivers the expected results: 35 test units are available for trials with the original product under real conditions, which are carried out, evaluated and documented jointly – as a robust basis for decision-making before the investment.