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Q & A - Is Silicone Bakeware Safe?

Silicone bakeware safety is an important issue because silicone is quickly becoming a popular alternative to nonstick metal cookware. Silicone rubber is touted as a stable, inert material made from sand. But - Is silicone bakeware safe?

Specifically – Do chemicals move or migrate from silicone cookware into food? In what amounts do they migrate and are the chemicals that migrate toxic? After thoroughly researching the topic I can answer these questions about silicone bakeware safety.

What Is Silicone?

Silicone is a synthetic polymer with rubber-like characteristics. Another name for silicone polymer is polysiloxane because it’s made up of repeating chains of siloxanes.

Siloxanes are made from silicon (extracted from sand) and oxygen. Siloxanes may be low molecular weight, medium weight or a high molecular weight. They are also identified by structure, either cyclic or linear.

The types of cyclic and linear siloxanes found in silicone cookware are:

octamethylcyclotetrasiloxane (D4), 
decamethylcyclopentasiloxane (D5), 
dodecamethylcyclohexasiloxane (D6) 
octamethyltrisiloxane (L3), 
decamethyltetrasiloxane (L4), 
dodecamethylpentasiloxane (L5)

The first 3 in this list are cyclic siloxanes and the bottom 3 are linear. And they all have a low molecular weight. The numbers refer to the number of silicon-oxygen bonds that make up the chain.

The Research

Although there's not a ton of research on silicone cookware safety, what I did find was worrisome. Because there are two things all the studies I found agreed on –

When used at temperatures above 200° F silicone cookware releases VOCs into your air and siloxanes into your food.

Studies conducted from 2005-2016 found.

  • The fat content of food can affect how much migration occurs. Cooking meat in new silicone bakeware released 177 milligrams into each kilogram of meat.
  • At temperatures at or above 300° F migration of siloxanes increased rapidly and is above the 60mg/kg limit.
  • At 350° F the migration of siloxanes from new silicone cookware ranged from 150 mg/kg food up to 300 mg/kg of food. And siloxanes still migrated into food after 100 hours of use.
  • New silicone molds released higher levels of siloxanes than used molds.
  • Up to 200°F, silicone can be considered as inert based on low overall migration values.
  • At temps above 500° F there is an immediate and high release of siloxanes from both new and used silicone cookware.

The Answer

Silicone cookware is not safe for many reasons.

  • It releases the types of siloxanes (cyclic and low molecular weight) that are considered the most toxic.
  • It adds to your total exposure to these siloxanes. Other sources of exposure include personal care and cleaning products.
  • At common cooking and baking temperatures, the amount of siloxanes that migrate into your food is above standards set by European countries.
  • When you use silicone cookware some of the siloxanes are released into your indoor air. That means you can inhale them.
  • Two of the siloxanes that migrate from silicone cookware (D4 and D5) can accumulate in your body.

So, for now I suggest avoiding silicone for baking and cooking. That includes spatulas and nonstick parchment paper. Nonstick parchment paper is coated with silicone. A 2016 study found it releases siloxanes into baked goods.

Instead stick to Glass, ceramic, and stainless steel cake and muffin pans and baking sheets. Make glass and metal bakeware nonstick by coating with organic coconut oil.

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