In any food business, it is key to recognise and prevent risks such as 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. Particularly, it focuses on health and safety requirements that should be put in place to protect machinery operators and eliminate possible risks.
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.
In addition, 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.
The Three Production Zones
In managing food safety on the processing floor, it is key to first understand the environment. European standard EN 1672-2 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.
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 antimicrobial chemicals (disinfectants). They must therefore be corrosion-resistant and mechanically stable to prevent the surface from being negatively affected.
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.
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. These 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 or the approvals of the FDA. 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 or ISO 21469. For parts that will unavoidably come into sporadic contact with foods, approved lubricants as per NSF-H1 must be used.
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 less than 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 unavoidable threads 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.
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.
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.
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.