Selecting the right seals for the food industry

Seals in the food industry secure processes at a level where hygiene, product safety and plant availability are directly interlinked. Every connection, every seal and every interface determines whether media remain cleanly separated and production processes run stably.

In practice, this means: seals are permanently exposed to mechanical, thermal and chemical stress. At the same time, they must not have any influence on the product. Even minimal material deviations, unsuitable materials or incorrect designs lead to premature wear, increased cleaning effort or contamination risks.

The selection is therefore always made through the interaction of application, medium, temperature and regulatory requirements. Anyone who proceeds in a structured way here reduces downtime, extends maintenance intervals and ensures stable processes over long periods.

Requirements for seals in the food industry

Seals in the food sector are subject to significantly stricter requirements than in many other industries. In addition to the pure sealing function, hygienic and regulatory aspects are the main focus. Materials must be selected in such a way that they neither release substances into the product nor are impaired by media or cleaning.

A central factor is food conformity in accordance with applicable regulations such as EU 1935/2004 or FDA. In addition, resistance to cleaning processes plays a major role, as plants are regularly cleaned using chemical and thermal methods. Temperature and media resistance are equally relevant, as many processes operate under changing conditions.

Furthermore, seals must remain odour- and taste-neutral and be integrated into an overall hygienic design. Only when material, construction and operating conditions are precisely matched to one another does a permanently stable and safe solution emerge.

Legal requirements and approvals

• EU Regulation 1935/2004 for materials in contact with food
• FDA conformity for international applications
• EU 10/2011 for plastics in contact with food
• BfR recommendations for elastomers
• EHEDG guidelines for hygienic design
• 3-A Sanitary Standard for plants and components
• Verification through certificates and test reports
• Documentation on migration, material purity and processing

Suitable materials in comparison

A well-founded material decision is based on clear criteria such as medium, temperature, cleaning and mechanical stress. In addition, regulatory requirements and technical characteristics are included in the assessment.

The choice of the right material largely determines how reliably a seal functions in ongoing operation. Different materials react very differently to temperature, media and cleaning processes. A blanket selection based on standard materials is therefore rarely sufficient.

What is decisive is the precise matching to the specific application. While some materials handle steam and water particularly well, others show their strengths with oil-based media or chemical stress. At the same time, all materials used must meet the requirements for food contact.

The following shows which materials have become established in practice and where their respective strengths lie.

EPDM

EPDM is one of the most frequently used materials in the food industry. The material impresses with very high resistance to water, steam and many cleaning media. It is therefore particularly suitable for applications in dairies, beverage plants and wherever regular CIP or SIP processes take place. At the same time, EPDM offers good temperature resistance and a long service life in continuous use.

Silicone (VMQ)

Silicone is characterised by high temperature resistance and very good flexibility. This material is used particularly in sensitive applications where odour and taste neutrality are the focus. Silicone is therefore suitable for processes with high hygienic requirements as well as for applications with strong temperature fluctuations.

FKM (Viton)

FKM is used above all where seals come into contact with oils, greases or aggressive chemical media. The material offers high chemical resistance and is suitable for demanding process environments. However, in applications with hot water or steam, FKM shows limitations, which is why precise matching to the area of use is required.

NBR

NBR has good resistance to oils and is therefore frequently used in technical applications. In direct food contact, however, its use is limited and requires careful examination of the respective requirements and approvals. Typical use is in less critical areas or outside direct product contact.

Hygienic design and surfaces

• Avoidance of dead spaces and gaps
• Complete cleanability of all sealing surfaces
• Smooth, low-porosity surfaces
• Defined compression for reliable sealing
• Dimensionally accurate cut pieces to avoid leaks
• Integration into the overall hygienic design of the plant
• Minimisation of deposits and microbial risks

Resistance to cleaning (CIP/SIP)

Cleaning and disinfection processes are an integral part of food production. Plants are treated with high temperatures, pressure and chemical cleaning agents. These conditions place high demands on every seal used.

The material must remain dimensionally stable over the long term, even when regularly exposed to thermal changes. At the same time, it must neither harden nor swell due to chemical influences. Declining elasticity quickly leads to leaks and increased maintenance effort.

Materials such as EPDM and silicone have become established in this environment, as they reliably withstand both thermal and chemical stress over long periods.

Typical areas of application

• Dairies: steam, fat, frequent CIP/SIP cycles
• Beverage industry: CO₂, pressure fluctuations, fast cycle times
• Meat processing: fats, proteins, aggressive cleaning
• Filling plants: high cycle rates and changing media
• Piping systems: continuous media exposure
• Pumps and valves: mechanical stress and pressure
• Mixing and process plants: combined thermal and chemical influences

Common mistakes in selection

• Insufficient matching of material and application
• Selection of unsuitable materials for real process conditions
• Missing or incomplete certifications
• Wrong Shore hardness and unsuitable elasticity
• Incorrect design of compression and sealing geometry
• Underestimation of temperature cycles and media changes
• Neglect of CIP/SIP exposure
• Use of standard solutions without application testing

Selection aid by application

A structured selection always follows a clear sequence.

First the medium is considered, then temperature and pressure. This is followed by cleaning processes and regulatory requirements. Only on this basis is the material decision made.

Application	Recommended material	Special features
Hot water / steam	EPDM	Very good resistance
Sensitive foods	Silicone	Neutral and flexible
Oily media	FKM	Chemically resistant
Standard applications	EPDM / Silicone	Economical and robust

In addition, technical parameters such as Shore hardness, compression and setting behaviour play an important role in long-term function.

The right selection as the basis for stable processes

The selection of seals in the food industry has a direct effect on product quality, plant availability and maintenance costs. Precise matching between material, operating conditions and regulatory requirements ensures stable operations and high operational reliability.

Technical factors such as compression behaviour, recovery capability and gap bridging significantly influence service life. In combination with the right Shore hardness, this produces a seal that works reliably even under changing conditions.

A structured selection combines application, standards and material into a robust solution. This allows failures to be reduced, maintenance intervals to be extended and processes to be operated stably over the long term.

Frequently asked questions

Which seal is approved for food?

Seals are considered food-safe if they comply with requirements such as EU 1935/2004, EU 10/2011 or FDA. What is decisive is the specific verification through certificates and test reports for the material.

Which material is best suited for CIP and SIP cleaning?

EPDM and silicone have become established for CIP and SIP processes. Both materials offer high resistance to temperature, steam and chemical cleaning media.

When should EPDM be used?

EPDM is particularly suitable for applications with water, steam and frequent cleaning cycles. Typical areas of application are dairies, beverage plants and hygienic process systems.

When is silicone the better choice?

Silicone is suitable for applications with high temperatures, high flexibility and odour-neutral properties. Particularly suitable for sensitive foods and changing process conditions.

What role does Shore hardness play in seals?

Shore hardness influences elasticity, compression behaviour and sealing. Materials that are too hard seal less effectively at low compression, while materials that are too soft wear more quickly.

Why do seals frequently fail in practice?

Typical causes are an unsuitable material choice, failure to take account of cleaning, temperature or media, and an unsuitable sealing geometry.

Which standards are relevant in addition to EU 1935/2004?

Important additions are EU 10/2011, BfR recommendations, EHEDG guidelines and the 3-A Sanitary Standard. These specifications concern material, hygiene and construction.

How is the right seal selected?

The selection is made systematically via medium, temperature, pressure, cleaning processes and regulatory requirements. The suitable material is then determined.

Our rubber sheets

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