Food Safety & Silicone Seals: Not All Seals Are Created Equal

A critical step in food safety in the food service industry is the selection of appropriate sealing devices. Silicone is a revolutionary material made from non-toxic silica with desirable characteristics such as high resistance to extreme temperatures (from -155oF to 400oF) and resistance to some acids commonly found in food products. It can be easily molded into form-fitted shapes.

Not all silicone formulations are food safe, however. This article provides information on the different grades of silicone and a bit about selection for food safety.

Why Silicone is the Material of Choice for Food Safety

Silicone has replaced natural and synthetic rubber in the food service industry as the top choice for seals and gaskets – and for a good reason. Silicone can withstand a larger variety of environmental conditions while maintaining desired levels of flexibility than rubber. It also offers longevity and resistance to fouling, reducing maintenance costs and the likelihood of seal failures.

In addition to the properties described above, silicone also offers:

• Resistance to wide temperature ranges while maintaining the desired level of flexibility/hardness
• Resistance to a wide range of chemical and physical properties found in food service, including acidity, UV/sunlight, fats/lipids
• Neutral odor and taste, including resistance to fouling by algae and bacteria
• Resistance to long-term compression set
• Aesthetic features include a variety of colors and opacity
• Many seals and gaskets are available in stock in standard and metric sizes

Grades of Silicone

Silicone is useful in various food service applications, from seals to tubing to belts. Below is more information on the different grades of silicone and when food-grade silicone is required for food safety.

Food-Grade Silicone

The Federal Drug Administration (FDA) regulates food safety, including using materials that come in contact with food products (21CFR177 Subpart B and C). This can range from the seals on food containers, to the tubing in beverage dispensers, to a belt in a commercial cookie oven.

Food-grade silicone must meet FDA regulations with a limited number of materials, including limits on the types of curing agents permitted. Other considerations are if the seal will be a single-use item or if the seal needs to withstand repeated use. Questions about whether the material is suitable for contact with the food items such as acids and fats arise, and how well it will stand up to cleaning and sterilization methods.

Medical-Grade Silicone

Medical-grade silicone shares similar characteristics to food-grade silicone. Medical devices with silicone parts can include machines with seals and hoses made of silicone, but they can also include devices implanted on or in people. Medical-grade silicone is regulated by the FDA under several regulations, including the requirement to be sterile. As such, medical-grade silicone is often manufactured in a cleanroom.

Standard-Grade Silicone

Silicone products are in a growing number of applications from consumer to industrial needs. In standard applications, there is no limit on the types of additives or fillers. These products are often cheaper to produce and can come in sizes and shapes similar to those in food service applications. But if they do not meet FDA regulations for coming in contact with food items, they can leach dangerous chemicals into food items. They may also not perform as expected, like developing cracks, incorrectly sealing, reduced longevity, or other failures.

Selecting the Right Material for the Job

When it comes to seals and food safety, it’s imperative to choose the right material. Silicone can withstand high and low temperatures, and exposure to acids and other environmental factors. Plus it can be molded to fit many shapes and sizes. From seals to tubes to belts and much more, silicone is necessary in the food service industry.