Recognising and preventing risks

 Salmonella in sausages, listeria in cheese – the list of food scandals is endless. Significant risks in the food sector are caused by:

• — Biological factors: decay caused by micro- organisms and their toxins

• — Chemical factors: cleaning and disinfecting agents and lubricants

• — Foreign particles: from machines, often caused by corrosion or abrasion, or from other sources

When ensuring a machine’s design is hygienic, all the risks must be taken into account, and action must be taken to prevent or reduce these risks.

The basics – standards and directives

 Standards and directives form the basis that allows people to enjoy food without risk.

Implementing these  regulations  during production reduces the risks for the manufacturer and the consumer. The aim of the EC Machinery Directive 2006/42/EC is the protection and safety of consumers and operators  wherever  food comes into direct contact with machine parts and components. The application of standards and directives for design (EN 1672-2/EHEDG  Doc  8 and Doc 13) and materials (FDA CFR Title 21, ISO 21469, 1935/2004/EC) provides  additional support for food safety.

Machinery Directive 2006/42/EC

This directive focuses on health and safety requirements put in place to protect machinery operators. Possible risks should be eliminated. Special hygiene requirements apply to machinery intended for the preparation and handling of  food. The machinery must be designed and constructed in such a way as to avoid any risk of infection, sickness or contagion. This directive forms the basis for the EC conformity mark.

The three production zones

 The European standard EN 1672-2, Food processing machinery – Basic concepts, defines three production zones:

The food zone

This zone encompasses all system parts and components that are mounted directly in the food flow and come into contact with foodstuffs. Food may become contaminated and end up back in the product flow.

System parts and components that come into contact with foodstuffs must be easy to clean and disinfect. They should be corrosion- resistant, non-toxic and non-absorbent. A smooth, continuous or  sealed  surface reduces the chance of food getting caught  and leaving residue that is  difficult  to remove, making it a contamination risk. In addition, only special food-compatible lubricants may be used.

The splash zone

In the splash zone, machine parts and components come into direct contact with foodstuffs, but the food does not end up back in the product flow. Nevertheless, these parts must be designed and built according to the same criteria as those in the food zone.

The non-food zone

In this zone, the machine components do not come into contact with the product. However, the system parts used in this zone should be manufactured from corrosion-resistant materials and be easy to clean and disinfect, as sources of infection can develop over time.

For more information on standard EN 1672-2, please click here.

Selecting the material

 

In order to protect the food, the machine components must not deposit any substances during the production process that are harmful to health or that impair the taste or aroma, through either direct or indirect contact with the food. To make certain that the work carried out during the cleaning phase is safe, the materials used for the machine parts must not react with the cleaning agents or the anti-microbial chemicals (disinfectants). They must therefore be corrosion-resistant and mechanically stable to prevent the surface from being negatively affected.

Common materials 

Austenitic stainless steel

High-alloy stainless  steel  is  usually  the logical choice of material for the construction of a production system in the food industry. Typical materials include AISI-304, AISI-316 and AISI-316L (DIN material no.

1.4301/1.4401/1.4404), commonly known as V2A, V4A or INOX.

 

Aluminium

Aluminium is frequently used for construction. It is affordable and easy to work with and process. Typical aluminium grades include AlMg2Mn0.8, AlMgSi1 and AlMgSi0.5. Aluminium components can be rendered resistant to cleaning agents through the application of an additional coating or anodised oxide layer.

 

Plastics

Plastic components permitted to come into direct contact with food must comply with Regulation 1935/2004/EC and the Plastics Directive 10/2011 (replaces Regulation 2002/72/EU) or the approvals of the

FDA (CFR 21, Sections 170-199). In addition to resistance to strain, ease of cleaning is also an important factor in the selection of suitable plastic materials. They must not give off or absorb any hazardous substances. 

 Lubricants

Lubricating greases and oils must comply with FDA regulations (especially Section 21 CFR 178.3570) or ISO 21469. For parts that will unavoidably come into sporadic contact with foods, approved lubricants as per NSF- H1 must be used.

Click here for more information on selecting materials and lubricants.

Hygienic component design

 The application of EN 1672-2,  ISO  14159  and DOC 8+13 of the EHEDG forms the basis for the hygienic design of machines and components. These standards take into account the fundamental design elements that can be used in the construction of components and systems.

Surfaces

A high surface finish  is  absolutely  essential on components that come into contact with the product in order to reduce microbial contamination. This can be achieved by using a mean peak-to-valley height of 0.4 to 0.8 µm within the food zone. Components with a peak-to-valley height of ≤ 3.2 µm are often used in the splash zone.

Connecting pieces, threads

Connecting components such as screws, bolts, rivets and so on may cause hygiene problems. Open threads are difficult to clean and provide the perfect breeding ground for bacteria. Any threads that cannot be avoided should therefore be closed off with suitable covers and seals.

Inner angles, corners and radii

Very small radii and corners are always a hygiene risk as they are difficult to clean. The prescribed minimum radius is 3 mm.

Click here for more information on hygienic design.

  

The fundamental challenge of cleaning

 All manufacturers are liable for their products. In the food and beverage industry complete product safety, especially from a microbiological standpoint, must be ensured to protect the consumer. As such, one important aspect involves designing components and systems with hygiene and ease of cleaning in mind in order to guarantee exemplary cleanliness, shortest possible cleaning times and minimal expense.

To avoid drives failing in aggressive environments, for example, the component materials must have certain qualities that make them suitable for reliably withstanding the prevailing ambient conditions, as well as guaranteeing full functionality and a long service life. This applies to both the materials used for the drive unit and those used for interface components, such as connections and seals. 

Clean and safe!

 Many potential sources of contamination in food and packaging systems such as bacteria, chemical influences or corrosion particles in the factory can be eliminated with just a few design tweaks. Easy-to-clean, corrosion-resistant system components make food production safer.

When buying food, the consumer expects high- quality products that have been hygienically produced, dispensed and packaged by the food industry. That is why customer-specific process and factory automation solutions are an important part of any hygienic value-added chain.

This requires a partner who is experienced in the field of automation technology and has the best possible expertise with regard to suitable technical components, as well as a thorough understanding of all the processes along the value-added chains of system manufacturers and food producers. This is the only way to protect the consumer and the manufacturer’s brand.

Seals and lubricants that comply with FDA regulations are recommended for system components that come into contact with food. Depending on the requirements of the specific application, there is a choice of valve types either for normal cleaning or for applications using intensive foam cleaning. Intensive cleaning of machine parts can also wash out the lubricating grease and impair the operation of the components. Using dry-running  seals  ensures that the washed out machine components still function reliably.

Click here for more information on cleaning.

Click here for more information on food safety.