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O-Rings and Rubber Seals: Hidden Components that Can Affect Taste and Purity of Food and Beverages

Rubber seals, gaskets and O-Rings are used in a wide variety of products that come into contact with food and water products that we eat or drink every day.

Rubber seals, gaskets and O-Rings are used in a wide variety of products that come into contact with food and water products that we eat or drink every day.  Valves help contain, store and dispense these products to us daily and universally utilize elastomer seals.  There are also a variety of connectors and special fittings using O-Rings or seals that help move our food and water from manufacturer to grocery store, restaurant or utility.

The growth of new consumer products providing special coffees, filtration and other specialty food devices, previously only found in commercial kitchens has significantly increased interest and demand for rubber seals “safe for contact” with food or water.  The need for these products is no longer confined to large water utilities or food processing plants.

Aside from function, a key consideration for these O-Rings and seals is the rubber seals themselves not impacting food, water or beverage taste or purity. 

Food and Drug Administration

The United States Food and Drug Administration (FDA) regulates three different types of food additives, direct, secondary direct and indirect. 

Direct food additives are directly added to food like dyes or processing aids that stay with the food product until consumed.

Secondary direct additives are added to the food or water product during production but removed prior to end user consumption. (Mixed with the food as a processing aid but later removed by evaporation or filtration.)

Indirect food additives are substances that come into contact with food but are not intended to be added into the food products themselves.  Examples of indirect food additives would be food packaging and food processing equipment that would touch the food or water product but not necessarily mix entirely within it.  The Federal regulation that covers indirect food additives and most closely addresses rubber seals and elastomers in 21 CFR 177.2600.

This regulation recognizes some ingredients as inherently safe and identifies them as GRAS

 (Generally Recognized as Safe) for use in food or food packaging.  This regulation also provides maximum percentages of these ingredients that can be used within a rubber seal or O-Ring ensuring minimal impact on food or water that the seal might come into contact with.  This regulation provides rubber seal manufacturers guidance on GRAS ingredients and amounts that are allowed in an O-Ring or seal designed for indirect contact with food or water products. 


Rubber seal manufacturers with experience meeting these important FDA guidelines can offer a wide variety of O-Ring compounds suitable for contact with food or water per 21 CFR 177.2600 with reasonable minimums and quick delivery.  Additional safeguards include provision of Batch identification and Cure Date with every shipment to ensure complete traceability. 

Any applications that would have a rubber seal coming into contact with food or water should minimally require at least 21 CFR 177.2600 certification from your supplier.  Critical applications may require additional laboratory extraction studies of these elastomers in the fluid environment or outside organization approvals from NSF, (National Sanitation Foundation) UL, (Underwriters Laboratories) or a variety of specific national approval agencies worldwide.

Milk and Edible Oils Require Special Consideration 

Rubber Seals or O-Rings that come into contact with milk or edible oils (Plant based hydrocarbons) can quickly discolor and adversely affect these fluids.  These fluids will tend to extract carbon and other ingredients from a typical O-Ring or rubber seal and can quickly discolor milk and any type of fatty food or oil.  These kind of fluids require stringent quality carbon black and the use of a much smaller proportion of some ingredients within the O-Ring to ensure there is no contamination of these sensitive fluids.  Elastomers meeting requirements for use with milk and edible oils are typically described as “White List” elastomers referencing the objective of not discoloring milk.

3-A Sanitary Standards

The first standards for the hygienic design of equipment used in the dairy industry were introduced in the 1920s and became known “3-A standards” for the three associations that cooperated to improve equipment design and sanitation. (Regulatory Sanitarians, Equipment Fabricators, and Processors)

The organization, 3-A Sanitary Standards Inc. is the modern equivalent dedicated to represent these same groups in the promotion of hygienic design for food safety.  This organization provides knowledge and resources on hygienic equipment design and administers a Third Party Verification inspection program required for use of the modern 3-A symbol. 

Rubber seal manufacturers with experience in the dairy industry will offer a range of elastomers tested to meet the 3-A requirements and considered safe for indirect contact with milk or edible oils. 

Lubricants Used in Your Application

Many dynamic applications require lubricants to reduce break out friction or for ease of assembly.  If your application requires lubricant on the O-Ring or in the assembly, it is important to ensure the lubricant chosen does not impact performance of the rubber elastomer and will also meet applicable food standards.  An experienced rubber seal manufacturer can advise you about available lubricants that meet FDA or other standards and can provide the O-Rings pre-lubed if necessary to aid assembly.

Certifications That You May Require

Whether your product will have contact with food, water or the more sensitive milk products, there should be guidance from a trained rubber seal professional and proper certification from your supplier.

Proper Certifications and Batch Traceability should be provided and maintained at your facility to document your hygienic plan and status of rubber seals and O-Rings at your facility.  It is important to segregate these products from other “non-Food” maintenance items and ensure proper storage and handling to provide longest shelf life and protection from contamination.

Please contact your rubber seal professional for guidance on a proper elastomer for your application or certification and storage guidelines.

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