Choose wisely for your hygienic applications

Put simply, in addition to helping ensure consumer safety, correctly specifying a pump system for use in a hygienic application will help prevent bacterial growth, batch contamination and ultimately will reduce product waste. To achieve this, hygienic equipment needs to be carefully designed to ensure it is able to resist the build-up of process soils, and it must be easy to clean between uses.

There are also regulatory requirements to be considered when it comes to hygienic equipment. The Machinery Directive EC 2006/42, for example, requires that machinery intended for use with foodstuffs is designed and constructed in such a way as to avoid any risk of infection, sickness or contagion. This means that all surfaces in contact with foodstuffs must be smooth and have neither ridges nor crevices which could harbour organic materials. And they must be easy to clean and disinfect where necessary after the removal of any easily-dismantled parts.

Expert advice relating to the design features of hygienic equipment is available from the European Hygienic Engineering and Design Group (EHEDG), a global consortium of over 400 food processing equipment manufacturers whose aim is to ensure the hygienic design of process equipment. It publishes guideline documents and sets best practice, as well as certifying that equipment meets the highest standards of food hygiene, providing a globally recognised test method for establishing the cleanability of hygienic equipment, using a specified cleaning and testing regime. The latest version of the EHEDG Guidelines was published in March 2018 and this document can be freely downloaded from www.ehedg.org. Equipment certified by EHEDG offers the user a guarantee that the product meets strict engineering principles, stringent design guidelines and test procedures.

EHEDG was started by Unilever in 1989 following a series of food contamination issues. Despite its best efforts to clean the plant between production runs, the company found that contamination and spoilage organisms were still being carried from one batch of food to the next. Unilever realised that the problem must, therefore, lie with the design of equipment. With a number of its competitors suffering from the same issues, EHEDG was born.

It is important to bear in mind that hygienic design is not just about ensuring product safety. It can also offer operator benefits in terms of reductions in cleaning times as well as providing substantial savings in the amount of water and chemicals needed for cleaning. For this reason the ease of cleaning and maintenance of pump systems should form part of the total cost of ownership (TCO) equation. Capital outlay forms just a fraction of the total operating expense. Watson Marlow Fluid Technology Group (WMFTG) warns against falling into the ‘cheapest is best’ trap. This, says the company, is short sighted for hygienic applications and it is important to look at overall product performance, reliability and suitability of equipment for an application. There is little point in buying a cheap product if it ultimately costs more in terms of maintenance, installation or integration into a machine or system. The MasoSine pump range, for example, has full steam-in-place and clean-in-place compliance and offers the reassurance that it has been designed and tested to meet the requirements of EHEDG Type EL Aseptic Class I.

Paul Green, UK sales manager for AESSEAL, moves the discussion on. He explained that ensuring you have a suitable pump system requires more than just specifying a hygienic pump. He said: “Mechanical seals are crucial to the reliable function of processing equipment. Despite this AESSEAL has identified a serious knowledge gap around key pieces of regulation relating to them. As a result, mechanical seals manufactured from unsafe materials are routinely specified in pump design and ongoing maintenance, creating a hygiene risk at several points along a production line.”

Food Contact Materials regulation EC 1935/2004 states that any mechanical seal on a food and drink production line must be 100% traceable and a statement of compliance must be clearly marked on the packaging it comes in. > 24

“The complexity of source materials and supply chains means that traceability can very easily get lost along the way,” continues Paul. “Those who work with an external supplier to maintain their equipment also assume – sometimes incorrectly – that the supplier has properly interpreted and implemented safety legislation.

“Our advice to companies seeking to guarantee compliance is simple. Look at the label and if the seal comes in packaging which does not clearly state its source, do not use it. This is the easiest solution to a potentially serious problem within hygienic applications.”

Eric Partington, chairman regional section of the European Hygienic Engineering and Design Group (EHEDG), also commented on issues relating to the selection of materials when putting together a pump system for hygienic applications. He said: “Article 3 of EC 1935/2004 demands that materials shall not transfer their constituents into food at levels harmful to human health.

“The end user must be able to correctly describe the conditions, in detailed technical terms, to the supplier so that they can react appropriately and select the correct materials for a particular application. Simply telling a supplier that a pump will be for food use is not good enough! It is the responsibility of the operator to determine the operating conditions under which the equipment will be expected to perform. It is important that the supplier knows the chemistry of the products being pumped, the temperature of the pumped product and for how long the product will be in contact with the material. Similar information is also required for any necessary cleaning procedures,” continued Eric.

For metal, alloy and glass demonstrating compliance with EU legislation can be covered by proving ‘significant and relevant past experience’. Stainless steel, for example, has been proven over many years in food production plants, as has nitrile rubbers and PTFE. However, where there is no such significant and relevant past experience of a material then it is necessary for the material to be tested in order to demonstrate that any constituents that may be released into a processed product are below the levels stipulated by the World Health Organisation.

Eric continues: “It is a common misunderstanding that the way around food contact materials legislation is for the buyer simply to stipulate that all food contact materials must be FDA approved. This is not the case,” warned Eric. “It is a meaningless claim and is insufficient to meet the obligations laid down inthe UK. It is compliance with EC 1935/2004 that must be demonstrated.”

So, while the primary responsibility for meeting EC 1935/2004 lies with the equipment supplier, the end user does have a secondary responsibility to provide its supplier with sufficient technical data for them to be able to ensure compliance. According to Eric, the buck actually stops with the person who puts the materials and equipment in contact with the product.

In conclusion, when hygiene is an issue it is important to choose wisely. Buying decisions for products used in hygienic applications should never be made solely on price and it is important to have good technical dialogue between the equipment manufacturer and the user. As stated in the EHEDG Guidelines documents it is more effective to incorporate hygienic requirements into the initial design because upgrading an existing design can be prohibitively expensive and may fail. Benefits are not only product safety but also the potential of increasing the life expectancy of equipment, reducing maintenance requirements, enhancing sustainability and lowering operating costs.