Hygienic design — a food industry essential

Mechanical engineers are great at sorting the generation, distribution and use of energy; the processing of materials; the control and automation of manufacturing systems; the design and development of machines; and solutions to environmental problems. But in the food industry this is not enough.

The food industry places hygiene, cleanliness and cleaning demands on its systems that go far beyond the standard in classic mechanical engineering. And there can be no compromising when it comes to hygienic design and how well a system can be cleaned. Product safety is the top priority.

In the beverage industry, be it alcohol-free refreshment beverages, fruit juices or near-water beverages, as soon as sugar, fruit aromas or vitamins are added, the susceptibility to microorganisms and the risk of contamination increases. To protect the integrity of the beverages, sterile and hygienic process management is essential.

Dr Jürgen Hofmann, engineer and chairman of the German Section of the European Hygienic Engineering & Design Group (EHEDG), well understands the requirements for cleanliness in the production of food. For him the starting point of each strategy for avoiding contamination is the design aspect of the systems — in other words the hygienic design.

This is based on the philosophy that each production line is only as good to clean as its weakest link. All components, pipes, connections and seals as part of the overall hygienic concept have to be as simple and residue-free to clean as possible. An important aspect is the material itself. All components that come into contact with the foodstuff have to be made out of corrosion-resistant stainless steel along with food-safe, regulation-conforming plastics and elastomers.

Pumps with hygiene certificates

Whether the valves, pressure sensors or flow meters — each component must be easy to clean when installed. Take pumps for instance.

Without pumps the beverage industry could not operate as they are responsible for almost all tasks involved in the transport and movement of liquid and viscous foodstuffs. The diverse range of pumps available means that even soft and sensitive solids, such as fruit pulp or whole fruits, can be transported without being damaged.

Many centrifugal and displacement pumps are EHEDG certified, which indicates that they are easy to clean. However, this is not sufficient to ensure the pumps are suitable for use in hygiene environments. The installation is also critical.

Pumps have to be installed so that they can be completely emptied. "In the case of multi-stage power units only the vertical execution normally guarantees a complete emptying via the suction pieces," Jürgen Hofmann asserts.

Clean right into the last corner

One of the biggest challenges for food and beverage manufacturers is coordinating their batch-mode production lines with their cleaning processes. An automatic cleaning (CIP, cleaning in place) with a subsequent sterilisation (SIP, sterilisation in place) is necessary in between the individual batches. This involves automated processes, during which acids, alkalis, disinfectants and saturated steam circulate in a cycle.

Pumps are essential here too, ensuring that fresh cleaning agents are led to the surfaces to be cleaned in regular intervals and that impurities are transported away. Pumps that fulfil all the demands of hygienic design are not only free of dead space and thus CIP cleanable, but can also be used as CIP feed pumps.

Electropolished, high-quality stainless steels also contribute towards good CIP abilities. Cr-Ni-Mo austenitics are molybdenum bearing austenitic stainless steels with very good corrosion resistance in many aggressive environments. The molybdenum addition ensures more resistance to pitting and crevice corrosion in chloride containing media and chemical environments such as sulfuric acid compounds, phosphoric and acetic acids. 1.4404 or 1.4435 (316L) stainless steels are considered to be state of the art.

Experience hygienic design live

Hygienic equipment including pumps, measuring instruments, separators, heat exchangers and fittings which can be integrated CIP processes will all be on display at Anuga FoodTec 2018. This exhibition will be held in Cologne, Germany, from 20–23 March next year.

Hygienic design will not only be on display on the exhibitor stands, but will also be addressed in detail in the event’s supporting program where lectures focusing on hygienic design and individualising the beverage industry will be among the highlights.

Image credit: ©Alexander Kosarev/Dollar Photo Club