Up to standard?

In this, the final article resulting from the HYFOMA project, Jacques Kastelein and Hilde Cnossen of TNO outline the reasons why equipment certification is essential to the food industry.

Need for hygienic design

Good hygienic design of process equipment has a tremendous impact on diminishing the risks of contamination of food during production, resulting in an extended shelf life of food products. Process equipment with poor hygienic design will be difficult to clean. Therefore, good hygienic design and preventive maintenance of production systems are essential prerequisites for high quality and safe products.

Upgrading an existing equipment design to meet hygiene requirements can be prohibitively expensive and may be unsuccessful. Hygiene requirements are most effectively incorporated into the initial design stage. The long-term benefits are product safety and the potential to increase the life expectancy of equipment, reduce maintenance and consequently lower operating costs. A good hygienic design and optimal integration of systems can be considered as proactive risk management.

Legislative requirements

Processing equipment should meet the requirements of the Machinery Directive 98/37/EC. If the manufacturer has assigned the ‘CE mark’ to its equipment and process lines the production of safe food should, in theory, be assured. However, the CE mark, which is granted on the basis of the Machinery Directive, clearly falls short of hygiene requirements. Even if the manufacturer meets the additional hygiene requirements formulated in the European Standard EN 1672-2 (1997), the microbiological safety of the foods produced cannot be ensured. The specific hygienic design of most equipment is not covered by such standards. Additional guidelines on hygienic design are therefore still needed.

Guidelines, published in the EHEDG series, have been developed, partly within the HYFOMA project, to support equipment manufacturers and users in food industry in their decisions regarding hygienic engineering, design and food processing. Parts of the hygienic equipment design criteria have been adopted by CEN working parties and have been included in the updated version of EN 1672-2 (draft, 2004) and the recently published EN ISO 14159 (Safety of machinery – Hygiene requirements for the design of machinery), giving general hygiene requirements.

Procedures for evaluation, testing and certification

In addition to guidelines for hygienic engineering and design, procedures for evaluation, testing and certification of process equipment and components have been established. Hygienic design of equipment and components can be verified by these procedures, which are described in a validation scheme and a certification scheme. These procedures are used by authorised test institutes. Authorisation of test institutes by EHEDG is required before conducting the testing and certification procedures.

Evaluation and testing

For process equipment manufacturers it is important to have the design or prototype evaluated and tested against given criteria, according to the validation scheme. The hygienic design of equipment is subsequently assessed and its cleanability can be tested. Such tests identify weak points in the hygienic design, including areas where product residues may accumulate or where micro-organisms can survive and multiply during prolonged production time.

Two guidelines are important in evaluating the hygienic design of process equipment and components. The guideline on Hygienic Equipment Design Criteria (EHEDG Doc. 8 ) discusses the principles of design criteria to be met for hygienic and aseptic process equipment. It gives guidance on how to design and construct food processing equipment and components such that it does not adversely affect the microbiological safety and quality of the food product. The susceptibility of the food product to microbial activity determines whether hygienic or aseptic equipment is required in the processing and packing operations. The guideline on in-place cleanability of food processing equipment and components (EHEDG Doc. 2) describes a test procedure to identify areas of poor hygienic design, where food products and/or micro-organisms can accumulate. The method is based on a comparison of the cleanability of the test object with that of a reference pipe with a known surface roughness. The degree of cleanliness is based on the removal of a bacteria-containing soil, which is assessed by evaluating the growth of bacteria remaining on the surface after cleaning. Cleaning is performed using a mild detergent to leave some soil in the reference pipe, which facilitates cleanability comparisons between the test object and the reference pipe. The test is intended as a basic screening test for hygienically designed equipment and is not indicative of performance in industrial cleaning situations. When the design is proven to be hygienic, the equipment and components can be certified.

Certification

A certification scheme following the principles of EN 45011 ‘General criteria for certification bodies operating product certification’ was set up. The certification programme will be implemented by the European Hygienic Engineering and Design Group (EHEDG).

The process of testing and certifying equipment and components is carried out by authorised organisations (see panel). Tests are conducted according to ISO 17025 (ILAC Guide 15; EN 45001) and the EHEDG certificate is granted under EN 45011 (ISO/IEC Guide 65; EAL G28) conditions.

Why certify equipment?

Certified equipment and components are evaluated, tested and certified according to relevant hygienic design criteria and legislation. This ensures that the equipment is of a good hygienic design and therefore easily cleanable. Also the applied materials for construction fulfill the requirements (FDA, BfR etc.) for design and application. This results in the following:

• Less frequent cleaning
• Increased life time of equipment
• Allows for less frequent preventive maintenance
• Extended shelf life of food products
• Lower risk of product (re)contamination during processing and packing

The additional manufacturing costs of hygienically designed equipment – and therefore the purchasing costs – are minor compared to the costs a food producer will save on use of cleaning agents (environmental issues), water consumption, maintenance and losses of production time. In practice, recall actions owing to food contamination are more frequent on food products produced by either manual handling or by poorly designed production plants and process lines in which accumulation of micro-organisms and biofilm forming occurs. Sometimes the costs of one recall action can be greater than the building and construction cost of the entire plant However, it is important to remember that buying a certified piece of equipment is only the start of a process that assures the whole line is correctly designed, installed and validated for cleanability. One hygienically flawed component between 30 perfectly designed components will still put the production of safe food at risk.

Leading food manufacturers in Europe and abroad require conformity of their food process equipment with the EHEDG hygienic design criteria. Since 2001 more than 80 certificates have been issued to equipment manufacturers stating that their equipment has been designed in conformity with the Hygienic Equipment Design Criteria (EHEDG Doc.8). Certified equipment is listed on www.ehedg.org/f_cert.htm.

References

1. Hygienic equipment design criteria, EHEDG Document 8, 2nd Ed., 2004
2. A method for the assessment of in-place cleanability of food processing equipment, EHEDG Document 2, 3rd Ed., 2004
3. Directive 98/37/EC of the European Parliament and of the Council of 22 June 1998 on the approximation of the laws of the Member states relating to Machinery
4. EN 1672: Food Processing Machinery – Basic Concepts – Part 2: Hygienic Requirements (1997; update 2004)

Acknowledgements

The HYFOMA project was funded by the European Commission under the Fifth Framework Programme – Quality of Life and Management of Living Resources (QoL), Key Action 1 (KA1) on Food, Nutrition and Health (QLK1-CT-2000-01359). We would also like to thank J. Hofmann (TUM, DE), A. Timperley (CCFRA, UK), J. Kold (DTI, DK), G. Wirtanen (VTT, FI), T. Bénézech (INRA, FR) and others.