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Hygienic Design in Food Industry

01 March 2015

Experts estimate the share of time spent with cleaning processing in the food and beverage industry to be up to 30 per cent.

It is, therefore, not surprising that the producers place great importance on the cleaning-friendly design - hygienic design - of their machines during the construction phase.

The aim: To achieve optimal hygienic conditions with the least possible investment of time and cleaning agents.

The central idea of hygienic design can be summed up fast: It is always about preventing microorganisms or impurities of any kind from affecting a food product using constructional measures.

A central aspect here is that the machines and systems are easy to clean. However, what might seem simple is in fact no easy task. EHEDG, 3A or material specifications of the FDA - the list of hygiene requirements is long.

For Dr Jürgen Hofmann hygienic design is however not a book with seven seals, but quite simply the answer to the question: How can the system be optimally cleaned?

He said that many sources for the danger of impurities can be avoided using simple constructional details.

"One only has to talk to a member of the cleaning staff to understand that sharp edges are less favourable than smooth transitions," said Dr Hofmann.

His engineering office advises mechanical engineers and food producers, who want to gear up their systems for improved hygiene.

The Chairman of the German division of the European Hygienic Engineering & Design Group (EHEDG), knows from years of practical experience, what has to be taken into account so that these are easy to clean: Namely, particularly avoiding gaps, recesses, constructional cavities and flow-free zones, because here there is the increased risk of deposits and biofilms.

Typical design features that FrieslandCampina also took into account when it came down to putting the new dessert and yoghurt line in Gütersloh into operation.

Almost 2,000 actuators and valves ensure that the networked system comprising of pipes, heaters and stainless steel tanks works accurately - in the heart of the sensitive process field, where cleaning agents and water are regularly used.

Valve terminals by Bürkert, which were installed into the hygienic design casing, make the "short cuts" to the actuators and sensors possible.

The switch cabinets offer protection against the toughest wash-down attacks with high-pressure cleaners.

A blue silicone seal, which is resistant to all types of cleaning agents, guarantees absolute impermeability.

Overhanging sloping rooves with a 30-degree angle and horizontal drip edges on the casing ensure that liquids drip off quickly and reliably.

Stainless Steel Equals Hygienic Design?

In addition to construction in accordance with hygienic criteria, the selection of the materials that are used for building the machines and systems also plays an important role.

Stainless steel is generally considered to be the most hygienic material of all.

However Jürgen Hofmann warned: "Stainless steel corrodes too under certain conditions!"

Chlorides that are found in cleaning agents and even in the food itself are the cause. The corrosion depends on the state of the surfaces.

Dr Hofmann said: "It is essential that the areas that come into contact with the products are good quality. Initially passivation, for example electro-polishing, and a medium surface roughness of max. 0.8 micrometres guarantees this."

An own working group of the EHEDG occupies itself with the chemical treatment of stainless steel surfaces. It is responsible for one of the numerous guidelines that defines the criteria for cleaning-friendly design. Furthermore, the EHEDG certifies components, which satisfy these requirements.

However, this alone is no guarantee that the system is in a hygienic state. Even on installing a certified sensor, it is possible for the entire measuring point to become unhygienic.

The weakest link always determines the cleanability of a system - which can slow down any optimised cleaning in the place process.

But when is CIP cleaning possible and when do the systems have to be hand-cleaned because product residues can't be completely flushed out?

Being able to dismantle the system easily - i.e. hygienic design - definitely becomes a focal point if you can't get around opening the machine.

Machines "geared up for hygiene" not only contribute towards increased food safety - they also increase the productivity

Food manufacturers will find answers to these questions at Anuga FoodTec in Cologne.

Investments in hygienic design will be one of the focal points at Anuga FoodTec from 24 to 27 March.

February 2015

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