(SG Process Water, 2002) There are many locations on food industry sites where the potential for the proliferation of Legionella spp in water systems exists. These bacteria can give rise to a potentially fatal disease in humans, which is identified as legionellosis or as legionnaires’ disease.

This document applies to the control of Legionella spp. in any undertaking involving a work activity and to premises controlled in connection with a trade, business or other undertaking where water is used or stored and where there is a means of transmitting water droplets which may be inhaled, thereby causing a reasonably foreseeable risk of exposure to Legionella spp.

The guidelines summarise the best practice for controlling Legionella in water systems. It consists of two parts; namely, Management Practices and Guidance on the Control of Legionella spp. in Water Systems.

The first section describes a management programme, which includes the key elements of : risk identification and assessment; risk management (incl personnel responsibilities); preventing or controlling risk of exposure to the bacteria; and record keeping.

The second part provides guidance on the design and construction of cooling systems, and hot and cold water systems as well as the management and monitoring of these systems. Water treatment programmes, with  attention to cleaning and disinfection, are also discussed.

SG Mechanical Seals, 2002) This guideline compares the design aspects of different mechanical seals with respect to ease of cleaning, microbial impermeability, sterilisability or pasteurisability.  As such, the document can serve as a guide for suppliers and users of this important component in food processing equipment.

Using EHEDG definitions, mechanical seals are classified according to use in the food industry into three categories: Aseptic, Hygienic equipment Class I, and Hygienic Equipment Class II.  The guideline covers both single and dual mechanical seals under the first two categories, which by definition, are subject to more stringent hygienic demands.  General design criteria are described, as well as the basic requirements for materials used for components in mechanical seals food applications.  Materials covered include carbon-graphite, ceramics, elastomers and metals. Hygienic implications of seal elements and components are also discussed.  Finally, installation requirements are described and illustrated, taking into account the product environment side, the flushing side and the cartridge design.

SG Dry Materials Handling, 2003)  The hygienic engineering of plants for processing dry particulate materials requires that buildings and each item of equipment be hygienically designed (EHEDG Doc 22).

This document describes general engineering guidelines to be applied to ensure that buildings, individual equipment items and accessibility of equipment when integrated within the plant layout are designed so that aspects of the process operation, cleaning and maintenance comply with hygienic design standards.

It details requirements related to plant enclosure, including hygienic zoning, building structures and elements (from floor to ceiling)  as well as process line installation.  Attention is also given to air stream and water related aspects within the plant as well as cleaning and contamination aspects.

These general guidelines are applicable to the early stages of overall plant engineering or to an existing plant, which needs upgrading to comply with hygienic design standards.

SG Process Water, 2004) Water is a vital medium used for many different purposes in the food industry. Systems for storing and distributing water can involve hazards , which could cause water quality to fall below acceptable standards. It is therefore critical to ensure that water storage and distribution in a food manufacturing operation takes place in a controlled, safe way.

This Guideline summarizes the best practice for three water categories used in the food industry: product water, domestic water and utility water.

Reference is made to Doc. 24 "The prevention and control of Legionella spp (incl Legionnaires' Disease) in Food Factories", 2002 also produced by the subgroup Process Water.

The choice of the most suitable water treatment depends on the water source and intended applications. Referencing CODEX, WHO and EU Directive 98/83/EC, the Process Water subgroup discusses in this document various techniques in relation to main hazards, 3 sources of which are namely: mechanical design and building; normal operation (including stops); and external factors.
Ion exchange, membrane filtration, chlorination/ozonation, and ultra-violet radiation are among the treatments discussed. Other titles from this subgroup are: The prevention and control of Legionella spp (incl Legionnaires' Disease) in Food Factories (2002) and "Safe Storage and Distribution of Water in Food Factories (2004).

This document addresses packing systems of solid food products and supplements an earlier guideline on "Hygienic packaging of food products", produced by the same subgroup (packing machines). 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. This title is the fourth in the EHEDG series of guidelines on packing machines, which includes: "Aseptic packaging of food products" and "Challenge testing of machines for liquid and semi liquid products"

The controlled properties of air, especially temperature and humidity, may be used to prevent or reduce the growth rate of some micro-organisms in manufacturing and storage areas.  The particle content - dust and micro-organisms - can also be controlled to limit the risk of product contamination and hence contribute to safe food manufacture.  Airborne contaminants are commonly removed by filtration.  The extent and rate of their removal can be adjusted according to acceptable risks of product contamination and also in response to any need for dust control.

These guidelines are intended to assist food producers in the design, selection, installation, and operation of air handling systems.  Information is provided on the role of air systems in maintaining and achieving microbiological standards in food products.  The guidelines cover the choice of systems, filtration types, system concepts, construction, maintenance, sanitation, testing, commissioning, validation and system monitoring.  They are not intended to be a specification for construction of any item of equipment installed as part of an air handling system.  Each installation needs to take account of local requirements and specialist air quality engineers should be consulted, to assist in the design and operation of the equipment.

Because these plants handle moist products in an airborne state, they are susceptible to hygiene risks, including a possible transfer of allergens between products. It is therefore critical to apply hygienic design considerations to both the process and machinery to prevent occurrence of
such risks. The Dry materials handling subgroup addresses these issues in
detail in their latest document. Starting from the basics with regard to the design, construction materials, layout, and zone classification of the drying systems to meet hygienic requirements, the subgroup then outlines component design aspects of the processing chamber, with particular attention to the atomization assembly and the distribution grids for fluidization. Systems for both supply and exhaust air should operate in a hygienic manner and the document lists recommendations for the use and installation of various types of filters. Finally, operational aspects, including sampling, control and general housekeeping are briefly discussed.

August 2005. This Guideline aims to offer a practical 'handbook' for those responsible for the specification, design and manufacture of food processing equipment. Its purpose is to offer guidance on the ways in which materials may behave such that they can be selected and used as effectively as possible. It is hoped that this Guideline will serve as an aide-memoir during the design process, so that equipment manufacturers and end-users 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.

Discharging systems for dry particulate materials (powders) are of importance since they aim at the transfer, in this case of dry solids, from one system into another without powder spillage, contamination or environmental pollution, and therefore relate to food processing safety. Dust control is an important issue around these discharging systems in relation to environmental hygiene and worker exposure.

The introduction of the product into the processing system is therefore a key step in maintaining the sanitation and integrity of the entire process. Many dry systems do not have any additional heating protective steps, as they are merely specialty blending processes. Therefore, any contamination that enters the system will appear to the finished product.

This document describes the hygienic design criteria for dry particulate materials discharging systems. Guidelines for the design of bag, big bag, container and truck discharging systems are presented.

These guidelines 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.

Hygienic and/or aseptic systems comprise inter alia individual components, machinery, measurement systems, management systems and automation that are used to produce for example food products, medicines, cosmetics, home & personal products and even water products. This horizontal guideline is about the hygienically safe integration of hygienic (including aseptic) systems, focusing on food production.

Systems and components are frequently put together in a way that creates new hazards, especially microbiological ones.  Deficiencies during the sequence of design, contract, design-change, fabrication, installation and commissioning are often the cause of these failures, even when specific design guidelines are available and are thought to be well understood. Errors in sequencing and content can also result in major penalties in terms of delays and in costs of components and construction. iely effectivelyuu  fficient plants and processes

This document examines integration aspects that can affect hygienic design, installation, operation, automation, cleaning and maintenance and uses system flow charts and cases describing the integration processes and decision steps.  It does not provide detailed guidance on specific manufacturing processes, products, buildings or equipment.

Abundantly illustrated, this paper provides guidelines for the correct execution of on-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 and the only welding method considered is the GTAW (Gas Tungsten Arc Welding, commonly known as TIG) without filler material (autogenous weld), since this technique is capable of assuring the best performance in the execution of welds for the fabrication of thin wall stainless steel tubing.  Inspection of welds will be covered in more detail in the next project.