Parchment paper that has been in direct contact with raw dough should not be re-used for food hygiene reasons.
The claims that unbleached parchment paper is better for the environment or safer is not supported by facts.
Baking parchment paper comes in two types, bleached or unbleached, and either silicone-coated or quilon-coated.
There’s a lot of talk about bleached paper and quilon online. Bloggers claim these are unsafe and bad for the environment.
They claim quilon is made of a “heavy metal” chemical, chromium. But chromium is classified as a transitional metal, so neither a heavy nor light metal.
Chromium is in three classifications based on the number of electrical ions.
Chromium-0 has no electrically charged ions. Chromium-0 is a hard stable form of chromium used in harden steel in metal production.
Chromium+6 has six charged ions. It is very unstable, so rare to find in the natural environment. The majority of chromium+6 is human-made for use in products like dyes, plastics, and paints. It is not used in baking paper.
Chromium+3 is stable and occurs naturally in our environment, including the foods we eat.
Chromium+3 is essential for insulin to regulate blood sugar levels, triglycerides, and cholesterol. Most multivitamins contain chromium which is essential for metabolism. I use multivitamin made from whole foods; it contains chromium.
Chromium+3 is naturally occurring in foods like whole grains, mushrooms, apples, broccoli, eggs, meats, tomatoes…the list goes on and on.
Chromium+3 is the type of chromium used to coat baking parchment paper.
While silicone may begin with a “natural” substance, it requires chemical processing to manufacture it into a usable product. This is true for just about all products we use in life.
A review of Wacker Chemie’s silicone baking paper patent application illustrates the complex chemical processes necessary to manufacture baking paper. It involves a lot of chemical processing.
https://patents.google.com/patent/US20170265480A1/en
Wacker is a large chemical manufacturing corporation.
https://www.wacker.com/cms/en-us/home/home.html
In 2003, the EU Commission for Health & Food Safety issued an opinion on the safety of silicone baking paper in which they concluded the method to cure silicone in manufacturing affected the types and amount of chemicals that migrated into food during baking on silicone-coated paper. It found silicone made using a dioctyltin oxide process resulted in the migration of monooctyltin and dioctyltin into food during baking.
While the vast majority of silicone-coated baking paper in Europe did not use a dioctyltin oxide process, 1.5% of baking paper did use the process. Its use in baking paper was subsequently discontinued in Europe.
All of this is to note that the level of safety of silicone baking paper depends on how it is manufactured.
https://food.ec.europa.eu/system/files/2020-12/sci-com_scf_out166_en.pdf
The claims that unbleached parchment paper is safe and better for the environment because it is “chlorine-free” is misleading as all paper is manufactured using chemicals. Sulfuric acid and concentrated zinc chloride are two chemicals commonly used in the manufacturing of parchment paper.
No matter what product we use, paper, silicone mats, cloth, etc, there is always some level of health risk, and certainly, all manufacturing affects the environment.