Guías EHEDG

"Easy cleanable Pipe couplings and Process connections" Version 4, July 2017

Second Edition, May 2017 - Pasteurization is a heat treatment aimed at reducing the number of harmful microorganisms to a level at which they do not constitute a significant health hazard. There are however many reasons why, in practice pasteurized products may present a microbiological health hazard. Due to the pasteurizer process design, the operation and control or inspection and maintenance of the pasteurizer there are a risk of unpasteurized or recontaminated product may reach the consumer. This document provides guidelines to avoid these issues.

Third Edition, July 2004, updated June 2007 - The method is intended as a screening test for hygienic equipment design and is not indicative of the performance of industrial cleaning processes (which depend on the type of soil). See Doc 15 for a test procedure designed for moderately sized equipment.

NOTE: Document was withdrawn in April 2018. Doc. 3 has been integrated into Doc. 46.

NOTE: Document was withdrawn in March 2016

Second Edition, July 2004 - Food processing equipment may need to be sterilised before use, and it is important to ensure that the sterilisation method applied is effective. Thus, it is necessary to determine under which conditions equipment can be sterilised. This paper details the recommended procedure for assessing the suitability of an item of food processing equipment for in-line sterilisation. It is advisable to conduct in-place cleanability trials (see Doc 2) prior to this test in order to verify the hygienic design of the equipment.

Second Version, May 2017 - Sterilization is a heat treatment aimed at destroying all vegetative microorganisms and spores to create a product which can be stored at ambient temperature yet minimizing public health hazard. There are however many reasons why, in practice sterilized products may present a microbiological health hazard. Due to the sterilizer process design, the operation and control or inspection and maintenance of the sterilizer there are a risk of untreated or recontaminated product may reach the consumer. This document provides guidelines to avoid these issues.

Second Edition, July 2004 - This document details the test procedure for assessing whether an item of food processing equipment, intended for aseptic operation, is impermeable to micro-organisms. Small motile bacteria penetrate far more easily through microscopic passages than (non-motile) moulds and yeast. The facultative anaerobic bacterium Serratia marcescens (CBS 291.93) is therefore used to test bacteria-tightness or the impermeability of equipment to micro-organisms. The method is suitable for equipment that is already known to be in-line steam sterilisable (see also Doc 5).

Third Edition, March 2018

This document describes the principles for hygienic design of equipment and factories intended for food manufacturing. The fundamental reason for applying hygienic design principles is to prevent contamination of food products. Equipment and factories of poor hygienic design are difficult to clean.

The document details the hygienic design principles that shall be followed when designing and constructing equipment and factories for manufacturing of foods. It gives guidance on design, construction and installation so that it does not adversely affect food safety and quality. These principles apply to open and closed manufacturing operations, surrounding facilities, all being cleaned either wet or dry.

Doc. 8 is used as a basis for hygienic design evaluation within the EHEDG equipment certification program.

The content of this document covers functional requirements, intended use, materials of construction, hygienic design and construction and assessment methods.

First Edition, July 1993 - This document describes the techniques required to produce hygienically acceptable welds in thin walled (<3 mm) stainless steel applications. The main objective was to convey the reasons and requirements for hygienic welding and to provide information on how this may best be achieved. This document is superseded by Doc 35, recently published. The subgroup will continue with a guideline on inspection of the quality of welds in food processing machinery.

Second Edition, May 2007 - Using the general criteria for the hygienic design of equipment identified in Doc 8, this paper illustrates the application of these criteria in the construction and fabrication of closed process equipment. Examples, with drawings, show how to avoid crevices, shadow zones and areas with stagnating product, and how to connect and position equipment in a process line to ensure unhampered draining and cleaning in-place. Attention is drawn to ways of preventing problems with joints, which might otherwise cause leakage or contamination of product.

NOTE: Document was withdrawn in April 2018. Doc. 11 has been integrated into Doc. 46.

First Edition, March 1994 - Thermal sterilisation is a process aimed at eliminating the risk of food poisoning and, when used in conjunction with aseptic filling, it aims to extend product storage life under ambient conditions. This is achieved by the destruction of vegetative micro-organisms and relevant bacterial spores. Liquid foods containing particulates are inherently more difficult to process than homogenous liquids due to heat transfer limitations in particulate liquid mixtures and the additional problems of transport and handling. This paper presents guidelines on the design of continuous and semicontinuous plants for the heat treatment of particulate foods. Ohmic heating techniques are not covered. See also Doc 1 on continuous pasteurisation and Doc 6 on sterilisation of liquid products without particles.

Second Edition, May 2004 - It is important that the plant design takes into account factors affecting the hygienic operation and cleanability of the plant. The risk of contamination of food products during open processing increases with the concentration of micro-organisms in the environment and their opportunity to grow in poorly designed equipment. This means that in open plants, environmental conditions, in addition to appropriate equipment design, have an important influence on hygienic operation. The type of product and the stage of the manufacturing process must also be taken into consideration. This paper deals with the principal hygienic requirements for equipment for open processing and applies to many different types, including machines for the preparation of dairy products, alcoholic and non-alcoholic drinks, sweet oils, coffee products, cereals, vegetables, fruit, bakery products, meat and fish. It describes methods of construction and fabrication, giving examples as to how the principal criteria can be met. See also guidelines on hygienic design criteria (Doc 8), hygienic welding (Doc 9), and the hygienic design of equipment for closed processing (Doc 10).

Third Edition, August 2020 - Valves are essential components of all food processing plants and the quality used strongly influences the microbiological safety of the food production process. These valves must therefore comply with strict hygienic requirements. The guidelines apply to all valves used in contact with food or food constituents that are to be processed hygienically or aseptically. Aside from general requirements with regard to materials, drainability, microbial impermeability and other aspects, additional requirements for specific valve types are also described. See also Doc 20 on double-seat mixproof valves.

NOTE: Document was withdrawn in March 2016

First Edition, September 1997 - This paper identifies and defines critical design parameters for welded pipe couplings: easily cleanable in-place; easily sterilisable in place; impervious to micro-organisms, reliable and easy to install. Gaskets of various types were tested for reliability and hygienic aspects using EHEDG cleanability test methods and repeated sterilisation. The objective was to provide a reliable dismountable joint which is bacteria-tight at the product side under the conditions of processing, cleaning and sanitation.

Fourth Edition, May 2020 - This updated guideline is meant to specify the technical requirements of pumps, homogenizers and dampening devices including their hygienic application in order to ensure a safe processing and production of food under hygienic conditions. The requirements described in the guideline apply to all pumps intended for the use in safe food processing, including centrifugal pumps, piston pumps, lobe rotor pumps, peristaltic pumps, diaphragm pumps, progressive cavity pumps, screw pumps as well as to homogenizers and dampening devices.

Second Edition, January 2014 - This guideline issued in January 2014 replaces Doc. 18 “Passivation of Stainless Steel” (1998) and includes new sections on pickling and electropolishing of stainless steels. Chemical surface treatments such as pickling, passivation and electropolishing can help to assure the successful functional and corrosion-resistant performance of stainless steels for product contact surfaces in the food and beverage industry. This document explains the general principles of those three processes above: Why they are necessary, when and how they should be applied, how they work and which chemicals are used.

Second Edition, June 2012 - Research has shown that hydrophobic membrane filters, with a pore size of 0.22 mm, do not retain micro-organisms under all process conditions. Investigations were conducted in risk assessment of sterilising hydrophobic membrane filters, evaluating the performance of the filters under a range of operating conditions. To validate the bacterial retention ability of sterilising grade hydrophobic membrane filters, a bacterial aerosol challenge test methodology was developed.

First Edition, July 2000 - This document describes the basic hygienic design and safe use of single-body double-seat mixproof valves. Today, food process plants incorporate various multifunctional flow paths. Often one piping system is cleaned while another still contains product. This simultaneous cleaning can potentially result in the dangerous situation where product and cleaning liquid are separated by just one single valve seat. Any cleaning liquid that leaks across such a seat will contaminate the product. Therefore, often two or three single seat valves in a "block-and-bleed" arrangement are applied.

NOTE: Document was withdrawn in April 2018. Doc. 21 has been integrated into Doc. 46.

Second Edition, March 2014 - Dry food processing and handling requires equipment that are different from those typically associated with wet and liquid products. This is the first in a series of documents that go beyond equipment design and covers installation and associated practices. In the case of dry materials, other considerations include material lump formation, creation of dust explosion conditions, high moisture deposit, formation in the presence of hot air, and material remaining in the equipment after shutdown. Appropriate cleaning procedures are described, dry cleaning being favoured to reduce risks of contamination.

Third Edition, September 2018 - This document is designed as a guide to the implementation and use of food-safe lubricants and lubrication practices. It is intended for use by food & beverage production companies (and other clean industries) but is also a guide for good lubrication practice for all industries. The document is suitable for use by audit companies and internal auditors and for this should be considered alongside suitable training also available from EHEDG.

Third Edition, September 2018 - This document is designed as a guide to the production, manufacture and supply of food-safe lubricants and lubrication practices. It is intended for use by lubricant producers but is also a guide for good lubrication practice for all industries. The document is suitable for use by audit companies and internal auditors and for this should be considered alongside suitable training also available from EHEDG.

NOTE: Document was withdrawn in March 2018. Doc. 24 has been integrated into Doc. 28.

Second Edition, October 2020 - This guideline concerns the design and selection of mechanical seals and seal auxiliary-systems that meet the hygienic and if specified aseptic requirements of food-applications. Requirements for design, materials, installation and operation of mechanical seals and seal auxiliary-systems are defined with respect to ease of cleaning, microbial impermeability, sterilizability and pasteurizability. The guideline is applicable for suppliers and users. 

NOTE: Document was withdrawn in March 2016. Doc. 26 has been integrated into Doc. 44.

NOTE: Document was withdrawn in March 2018. Doc. 27 has been integrated into Doc. 28.

Second Edition, March 2018

Since water treatments can be directly or indirectly part of the production process, this treatment should render the water microbiologically and toxicologically safe. Likewise, systems for storing and distributing water can involve hazards, which could cause water quality to fall below acceptable standards. It is therefore vital that water storage and distribution in a food manufacturing operation takes place in a controlled, safe way.

This Guideline is meant to provide guidance on hygienic and safety related issues concerning water management (sourcing, storage and distribution) and provides recommended practices for two water categories used in the food industry: product water, and utility water. Furthermore, it summarises appropriate practices for controlling Legionella in water systems.

First Edition, December 2004 - This document addresses packing systems of solid food products and supplements earlier guidelines. Solid food is characterised as having a water activity of >0.97, low acid, not pasteurised or sterilised after packaging, and distributed through the cool chain. Examples include fresh meat and some meat products, cheeses, ready meals, cut vegetables, etc. Hygiene requirements of the packaging operations, machinery as well as personnel, are described and reference is made to the American Meat Institute's principles of sanitary design. See also Docs 3 and 11.

NOTE: Document was withdrawn in September 2016. Doc. 30 was integrated into Doc. 47.

Second Edition, June 2018 - Applications in the food industry require that spray drying should meet hygienic processing standards and all components in contact with product should be hygienically designed and preferably be EHEDG approved. This document describes the design and operational features of spray dryer and fluid bed plants with integrated or attached fluid beds that produce food and food related products.

First Editon, August 2005 - This guideline aims to offer a practical handbook for those responsible for the specification, design and manufacture of food processing equipment. It offers guidance on the ways in which materials may behave such that they can be selected and used as effectively as possible. The properties and selection procedures with regard to metals, elastomers and plastics are covered in detail. Potential failure mechanisms and influences of manufacturing processes are also discussed. A more general overview of composites, ceramics and glass and materials is provided. The guideline can serve as an aide-memoir during the design process, so that equipment manufacturers and endusers can together ensure that all aspects of materials behaviour are taken into account in designing safe, hygienic, reliable and efficient equipment which can be operated, maintained and managed economically.

First Edition, September 2005 - The introduction of the product into the processing system is a key step in maintaining the sanitation and integrity of the entire process. Discharging systems are designed to transfer, in this case dry solids, from one system into another without powder spillage, contamination or environmental pollution. Many dry systems do not have any additional protective heating steps, as they are merely specialty blending processes. Therefore, any contamination that enters the system will appear in the finished product. Guidelines for the design of bag, big bag, container and truck discharging systems are presented. They are intended for use by persons involved in the design, sizing, and installation of bag, big bag and truck discharging systems operating under hygienic conditions.

Second Edition, August 2020 - This horizontal guideline is about the hygienically safe integration of hygienic (including aseptic) systems in a food production/processing facility. This document examines integration aspects that can affect hygienic design, installation, operation, automation, cleaning and maintenance and uses system flow charts and case studies describing the integration processes and decision steps. It does not provide detailed guidance on specific manufacturing processes, products, buildings or equipment.

First Edition, July 2006 - Abundantly illustrated, this paper provides guidelines for the correct execution of one-axis hygienic (sanitary) welding between pipe segments, or between a tube and a control component (e.g. valve, flow meter, instrument tee, etc.). It deals with tube and pipe systems with less than 3.5 mm wall thickness, built in AISI 304(L) (1.4301, 1.4306 or 1.4307), 316(L) (1.4401, 1.4404 or 1.4435), 316Ti (1.4571) or 904L (1.4539) and their equivalents. The requirements for a weld destined for hygienic uses are first described, then the possible defects which can affect the weld are listed, and at the end the procedure for a state-of-the-art welding execution is illustrated, including preparation of pipe ends, final inspection and a trouble shooting guide. It mainly refers to the part of the weld in contact with the finished or intermediate product.

First Edition, June 2007 - In this document, hygienic transfer systems for transport of bulk materials within a food processing plant are described. This document also covers situations where transfer systems are used as a dosing procedure. In principle, the less the need for product transfer within a food processing plant, the easier it is to make a factory hygienically safe. Furthermore, with a minimum of product transfer between equipment, there are the added advantages of a more compact plant, lower energy consumption and reduced cleaning time. Less product handling results in less adverse effects on product properties. This guidelines are intended for use by persons involved in the design, technical specification, installation and use of transfer systems for dry bulk particulate materials operating under hygienic conditions.

First Edition, November 2007 - This guideline is intended to advise both, sensor designers and manufacturers as well as those in charge of production machinery, plants and processes about the appropriate choice of sensors and the most suitable way for application in dry and wet processes. Sensors are crucial in the monitoring of the critical process steps as well as the CCP's as established by the HACCP study of the process. Therefore validation and calibration of sensors in time sequences are essential. This guideline applies to all sensors coming into contact with liquids and other products to be processed hygienically. However, it focuses upon sensors for the most common process parameters, particularly temperature, pressure, conductivity, flow, level, pH value, dissolved oxygen concentration and optical systems like turbidity or colour measurements. The objective is to provide a guideline clearly describing standard hygienic requirements and recommendations for sensors and corresponding process adaptations.

Second Editon, May 2017 - Rotary valves are widely used in the food processing industry for continuous discharging, metering and dosing of dry particulate materials from or into attached plant components. Such applications involve hygienic material handling and therefore only rotary valves of approved hygienic design should be used. This document describes the design and operational features of rotary valves that are of importance when rotary valves operate in a hygienic processing environment.

First Edition, June 2009 - In many areas there is an increasing demand for self stable products. However, microbial product contamination limits the shelf life of sensitive products which are not protected by any preservatives or stablised by their formulation. Products which fail this inherent protection have to be sterilised and in consequence, the equipment must be cleanable and sterilisable. Micro-organisms which are protected by product residues or biofilms are very difficult or impossible to inactivate and the same applies to process areas if resulting in a recontamination risk. This guideline is intended to describe the basic demands for equipment and process areas for aseptic food manufacturing.

First Edition, October 2010 - This Guideline describes in detail the hygienic requirements of butterfly valves, slide gate valves and ball segment valves. It also briefly mentions pinch-off valves, ball and plug valves as well as cone valves. The hygienic design requirements of rotary and diverter valves are subject of separate EHEDG Documents (Doc. 38 and 41).

First Edition, August 2011 - Every process plant is equipped with valves, which fulfil numerous functions. These include line shut-off, opening, change-over and control of product flow, while also giving protection against both excessive or insufficient pressure and intermixing of incompatible media at intersection points in the process line. Diverter valves are applied either when dry particulate material (product) flow has to be diverted into several directions during processing, or when product flow from different lines converges into one line. This Guideline deals with the hygienic aspects of diverter valve design.

First Edition, April 2013 - This guideline covers the hygienic aspects of disc stack centrifuges used to separate fractions of liquid food products or to remove dense solid matter from products. The hygienic operation of a disc stack centrifuge, which is a complex machine with the purpose of collecting non-milk-solids (NMS) or other solid matter from liquid products, relies on proper cleaning by CIP/COP. Therefore, this guideline deals with cleaning as well as design. The guideline does not cover cyclonic types of separators, decanters, basket centrifuges or other types of devices.

First Edition, April 2016 - This document provides guidance to the hygienic design of belt conveyors specifically for use in an environment where wet cleaning is mandatory, and is supplementary to the general requirements and standards for hygienic equipment. The guidance is relevant where the foodstuff is in direct contact with the conveyor and also in areas where there is a hygienic risk from indirect contamination. Although applicable for use in all food production environments, care must be taken when using these guidelines in considering the actual conditions, product types and the hygienic risks of contamination. Similarly, where a dry application precludes the use of water and liquids in cleaning, different systems may be suited, as described in EHEDG guideline, document 22.

First Edition, September 2014 - This document provides those responsible for the design and construction of food factories with best hygienic practice guidelines. Following the advice in this document should, therefore, ensure that the building will be designed to the minimum hygienic building design standards that are applicable worldwide. Whilst primarily aimed at food manufacturing sites, this guidance is also applicable to food service buildings. This document does not consider any international or national building standards or safety standards (e.g. fire). It also does not cover hygiene within the construction process which is intended to be provided via EHEDG guidance on maintenance procedures. This document does, however, assume that buildings will be constructed following general civil engineering best practice as failures in the construction process will lead to potential unhygienic features related to hazard harbourage and the reduction of cleaning efficacy.

September 2021

This guideline provides recommendations for establishing site specific cleaning validation, monitoring, and verification programs in a food manufacturing environment. It explains the overall concept and provides templates and practical examples that can be used in order to establish validation, monitoring and verification programmes. 

First Edition, April 2018 - This document on hygienic and aseptic filling machines for liquid products (foods as well as beverages) replaces EHEDG documents 3, 11 and 21. It gives guidance to manage and to monitor hygienic risks related to this kind of machines. This guideline gives guidance for selecting the appropriate machine class and determines the machine class according to design principles implemented. It includes a summary of decontamination requirements and gives an overview on microbiological tests used when qualifying hygienic filling machines.

First Edition, September 2016 - These guidelines focus on air handling systems installed for food factory building ventilation and its air quality control. Supply systems for process air, compressed air and exhaust air systems such as grease filter systems or dust removal units are excluded from the scope of this document. These guidelines are intended to assist food producers in the design, selection, installation, and operation of air handling systems to meet the air quality and hygienic requirements of the food manufacturing process.

First Edition, October 2017

The guideline is intended to provide guidance on hygienic design criteria for equipment manufacturers (when designing the equipment) and the plant for the fish industry (during the procurement process and installation, plant design and microbiological sampling). It stresses the current best practices in design of fish processing equipment and plant to highlight typical hazards and challenges of fish processing and emphasizes the importance of control of the environment.

This guideline does not cover other sources of hazards (air, water, personnel).

Microbial contamination of fish during processing may arise from various sources including processing equipment and plant that has not been hygienically designed or adequately cleaned and disinfected. All surfaces, whether in direct contact with product or not, may harbour sources of contamination of fish. Fish processing equipment reported as sources of pathogenic bacteria (particularly Listeria) include conveyors, washing tanks, trimming tables, gutting machines including vacuum systems, filleting, trimming, skinning and pin-boning machines, refrigerated water systems and ice-machines. Floors and drains are also important sources of pathogenic and spoilage bacteria in the plant.

To ensure safe product through adequate cleaning and disinfection programs, both the equipment and plant used for processing and handling food (fishery) products must be designed, fabricated, constructed and installed according to sound hygienic design principles.

Although different stages of processing and manufacturing may demand different risk based hygienic design solutions, the fundamental principle of the design of equipment must be to reduce the probability that relevant microorganisms may concentrate or be allowed to hide and increase.

First edition, July 2019

This guideline contains recommendations and requirements for hygienic design, user requirement specifications, management and validation of hygienic CIP installations that will assure a CIP of the different objects to be cleaned.

First edition, July 2021

This guideline aims to provide a basic understanding of the cleaning and disinfection of food manufacturing equipment and their environment. It is intended to help stakeholders within a food manufacturing facility to make the correct choices when developing cleaning programs by offering guidance on soil characteristics, wet and dry-cleaning methods, as well as disinfection methods.

The guideline can also help designers and manufacturers of hygienic entities to understand the needs of end-users when specifying and building these entities.

First edition, May 2020

The statements in this guideline can be applied to existing weld joints as well as to welds performed during fabrication or installation of new plant. The only materials considered herein are stainless steels in compliance with the requirements of the EHEDG guidelines. At the same time, this guideline can also be applied by plantoperators who wish to carry out weld testing on existing equipment within the course of a specified maintenance program. 

First Edition, May 2020

This guideline describes requirements for the hygienic design of equipment and production lines used in the bakery industry. It stresses the current best practices in the design of machinery and highlights typical hazards and challenges. It also assigns the dry or wet cleaning procedures to the different types of equipment.
The general part contains information on special characteristics of the production chain and of products, appropriate cleaning procedures, applicable materials and recommendations on the design of equipment in general. In tabular chapter 10, the individual process areas and related equipment of the baking process following unit operations are described. This part gives a résumé of poorly designed areas in contrast to recommendations on hygienic improvements. The tables listed in this chapter 10 comprise hygienic weak points in the bakery production equipment and provide approaches for their reduction and improvement. Rec-ommended cleaning procedures are given for the individual components. The tables are ordered according to the bakery production process. For greater clarity purposes, the tables are classified by the three main pro-cess areas:

• Raw material handling and raw material refining,
• Dough preparation and dough manufacturing,
• Oven and cooling.

These process areas are subdivided into unit operations and their components and machines, respectively.