The food industry has introduced a ground set of guidelines for hygienic design, thereby improving product quality, process efficiency and reducing environmental impact. And despite differences in processing food and pharma materials, the pharma production processes can find benefits by adopting similar guidelines.

The hygienic design process requirements are very similar in the food and pharma industries

European Hygienic Engineering and Design Group (EHEDG) was established in 1989. Since then, EHEDG has provided hygienic design guidance for the food industry. Since 2000, the guidelines have been supplemented by a certification scheme for components used in closed processes intended for cleaning-in-place.

The certification scheme has been extended along the way, and the focus of the guidelines has moved from mainly a components perspective, to being more holistic, and focusing on production plants, process lines, cleaning procedures and sound process execution.

Even though EHEDG is initially intended to benefit the food industry, many principles are valid for a broader audience e.g. when aseptic or sterile production is the focus, like in the pharmaceuticals industry. In principle, hygienic design is intended to make production equipment easier to clean, but also limit the risk of buildup of biofilm, which is equivalent to the risk of retaining allergens.

The processes of retaining biological and organic materials may be different in the physical and biological/chemical nature, but the process design requirements are very similar.

The benefits of proper hygiene in production processes

Product safety is non-negotiable when producing products for human intake. However, hygienic design has more benefits than ensuring safety for the end-user.

The benefits of a hygienic design process are improved product quality, reduced environmental impact and improved process-efficiency due to reduced maintenance costs and optimal cleaning processes. In many ways, hygienic design specifications capture essential aspects of product safety, which, if they are not monitored and managed properly during planning, design, installation and commissioning, may hamper the ability of a process plant/line to provide the intended high-end products.

Applying sound hygienic principles in the construction of production lines, having an efficient cleaning procedure, a valid cleaning validation and proper qualification procedures to test that the specifications are met, are all important to achieve good hygienic performance for food as well as for pharmaceutical companies.

The currently 44 EHEDG guidelines, plus a few additional documents, cover the following areas:

  • General Principles, Materials, Surfaces
  • Test Methods
  • Factory Design incl. Design of Utility Systems
  • Open Equipment
  • Closed Equipment for Liquid Food
  • Closed Equipment for Dry Particulate Materials
  • Packaging Machinery incl. Filling Machinery
  • Heat Treatment
  • Cleaning and Validation
New guidelines focus on the holistic approaches in processes e.g. issues pertaining to factory design, process line design, utility systems, process management and validation of the hygienic status of final installations.

EHEDG Certification scheme 

EHEDG certification follows two main classes: Wet processing, called EL, and dry processing, called ED. Both classes apply sub notation labeling equipment, suitable for cleaning-in-place Class I, and equipment that needs to be dismantled during cleaning Class II.

These are the only two options available for ED (dry processing), whereas the EL scheme (wet processing) also includes the certification Aseptic and AUX for auxiliary equipment. Thus, yielding four main groupings of certification:
  • EL Class I and II
  • EL Class I and II Aseptic
  • EL Class I AUX
  • ED Class I and II
The auxiliary class does not allow for equipment to be dismantled during cleaning. The EL Class I and EL Class I Aseptic are supported by accredited test methods described in EHEDG guidelines.

The prerequisites for certification are compliant with the relevant EHEDG guidelines and the basic criteria in Guideline no. 8, these being:
  • Food contact materials must comply to EU regulations and FDA
  • Surfaces must have a roughness lower than Ra = 0.8 µm and must be free of imperfections
  • Rounding radii of a minimum of 3 mm must be applied in corners (3-A specify 3,2 mm) or the angle must be open which requires an angle of 135⁰ or above
  • Surfaces must be drainable and a slope of minimum 3⁰ is required
  • Gaskets must be flush with the adjacent materials 
Naturally, there are discrepancies between ASME BPE and EHEDG in practice, but it doesn’t mean that the one or the other is generally stricter.

An EHEDG certification process is carried out at one of 8 EHEDG Accredited Test Laboratories. It is initiated by an Authorized Evaluation Officer (AEO) who will inspect drawings and physical components and, in some cases, defer the component to testing.

Hygienic integration and project management

Using hygienically designed components, preferably EHEDG certified, is only part of the process.

Hygienic integration of the process combines two hygienic entities together, whilst assuring that the assembly is hygienic and meets the requirements for further integration steps. In the final stage, this will be the integrated process line.

The process of getting from a set of user specifications for a process line to a properly working process line covers many activities. If this process is not formalized, there is a risk of challenging the hygienic performance. Such a formalized model is The Lifecycle Development Model or so-called V-model, due to the characteristic ‘V’ shape. (figure 1)

Figure 1: The Lifecycle Development Model. Specifications with increasing details are show on the left and qualification processes on the right-hand side of the “V” and testing according to protocols.

The model allows refinement and documentation of specifications, and a loop back to ensure that user requirements are revisited, and testing protocols updated accordingly.

The V-model is a framework comprising design (left hand side), execution (bottom) and commissioning (right hand side) of a project. It provides a logical sequence that organizes the complex activities of defining a project scope, executing it and finally qualifying it.

The qualification is critical for the hygienic performance. It is important that the performance qualification testing plan are adequately designed to test against the intended requirements otherwise the possible challenges in hygienic performance may not be reviled.

So, how can the pharma industry benefit from the food industry?

A simplified distinction between the two industries is that the food industry focuses on cleaning, while the pharmaceutical industry focuses on sterility. In both cases, product contamination must be avoided, but the legal demands are higher for pharmaceutical products.

The levels of cleanliness are different, and in food production, cleanability of the process equipment and effective cleaning followed by chemical disinfection is common. Whereas, in the pharmaceutical production, cleaning will be followed by steam sterilization. The application of steam for sterilization has traditionally led to less strict focus on the design of the equipment, and hygienic design as a discipline has been more developed and more extensively applied in the food processes where the cleaning step plays a pivotal role in assuring product safety.

Thus, there are learnings from hygienic design in food production which can benefit the pharma industry and provide better and safer processes. Naturally, there is much the food industry can learn from the pharma industry when it comes to Good Manufacturing Processes (GMP), and by exchanging experience and learnings, new standards can be made for a safe production of consumer goods.

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