“Silicone muffin trays contain or release microplastics during use.”

The migration of components, particularly siloxanes, into food poses potential health risks [13,14,15,16,17,18]. … This study established a migration testing framework incorporating both routine and extreme exposure scenarios to investigate siloxane migration from silicone FCMs. Analysis of the 30 silicone FCMs detected migration of 27 of the 35 target siloxanes, with migration levels ranging from 5, especially for individuals aged >13 years.

The purpose of this investigation was the study of the migration of silicone oligomers from SRBMs to food simulants. … In this study, under different conditions of usage including baking at 175°C, microwaving at 800W, and freezing at −18°C, the migration (70°C for 2h) of silicone oligomers from SRBMs to food simulants (isooctane, 95% ethanol, and Tenax®) was determined.

Methylsiloxanes (MSs) account for the largest proportion of NIASs in FCSPs and their migration into food/baking molds and bottle nipples have attracted much concern (Feng et al., 2016, Feng et al., 2022; Liu et al., 2021). … For example, investigation by Liu et al. (2021) found that after silicone molds were used under different conditions (baking, microwaving, and freezing), 18 CMSs (D4-D21) migrated into three food simulants at 70°C for 2h.

Professor Jones says that silicone utensils and cookware “tend to be quite inert and don’t break down very easily”. … While these products “can wear down and break up over time” the “particles that may result will be bigger than microplastics”. … After a long time or rough use “mechanical breakdown” can happen, but using silicone products conventionally shouldn’t cause smaller particles to form or shed.

The migrating substances consist principally of cyclic oligomeric polydimethylsiloxanes; however some samples contain a mixture of cyclic and linear oligomeric polydimethylsiloxanes. … The mass of these oligomers is between 450 and 1500 Daltons and the percentage of these polydimethylsiloxane oligomers lower than 1000 Daltons varies from 19.8% to 90.9%.

The migration of twelve cyclosiloxanes (from D4 to D15) and one linear siloxane (L7) have been identified and quantified in this study.

The main question was whether a significant degradation or even breakdown of the silicone elastomer could take place yielding enhanced migration of dimethyl siloxanes. … No formation of migrating siloxanes beside the initial amount in the new, unused moulds could be observed. … The physical properties of the silicone moulds remained almost constant during the experiment; no limitations in function due to the repeated thermal stress were observed.

Silicones can contain oligomers known as siloxanes, which are either by-products of the polymerization process or arise from chemical reactions during processing. … During the screening analysis of samples of 50 % ethanol at 100 ºC for 8 h a total of 112 different volatile compounds were tentatively identified by MS spectra and quantitatively estimated (LODs = 0.00005–0.014 mg/kg). … Most of the samples released cyclic polysiloxanes and also some aldehydes. Concerning the migration of substances found, it can be confirmed that there is not safety concern, as all of them complied with the Royal Decree 847/2011

The purpose of this investigation was the study of the migration of silicone oligomers from SRBMs to food simulants. … The obtained results show that silicone oligomers are released from SRBMs and possibly migrate into food.

Overall, the results demonstrate that silicone baking moulds release volatile compounds – including in some cases specific substances of concern – that migrate into food and thus can be ingested by consumers.

In February 2021, a German official food control laboratory tested various silicone bakeware products for the potential release of D3, D4, D5, D6 and D7 (Table 1) into food simulants. For some of the tested silicone FCMs, migration into vegetable oil (food simulant D2) and poly(2,6-diphenyl-p-phenylene oxide (MPPO)) (food simulant E) exceeded 5 mg/kg food significantly.

EFSA publishes a literature review on micro- and nanoplastics released from food contact materials. The findings show that these tiny particles can migrate from packaging or utensils into food, but at much lower levels than some earlier studies suggested.

There is not sufficient scientific evidence to show that microplastics and nanoplastics from plastic food packaging migrate into foods and beverages.

While the material can release silicone microparticles, or cyclic siloxanes, similar to microplastics, especially when heated or in contact with fatty foods, they are generally considered less toxic and less prone to bio-accumulation than microplastics. … On its website, the Plastics Pollution Coalition cited recent scientific studies using advanced imaging that have shown that silicone items, such as sealants, kitchenware, and baby products like pacifiers, can shed microparticles during use, aging, or exposure to high heat, mechanical friction, or certain cleaning agents. … “Unlike plastic, silicone does not break down into tiny microplastics,” the website noted. “Instead, sand-based silicone will eventually return to the Earth, rather than becoming plastic microbeads.”

Compared to other exposure routes, c-VMS contamination of cake from silicone moulds seems to be low, as demonstrated by the low concentrations of D4 and D6 measured.

However, concerns have emerged regarding the potential migration and release of siloxanes from these products into food and indoor air during baking. … This study evaluates human exposure to cyclic siloxanes via ingestion and inhalation, using silicone bakeware purchased on the Canadian market.

One widely marketed alternative is silicone, a flexible polymer made of silicon and oxygen that can be made into a rubbery substance. … But while the science on silicone is sparser than that on plastic, there is enough information to suggest we should be cautious about welcoming it into our kitchens, some experts say.

Like fossil fuel plastics, silicone is a synthetic substance that does not benignly biodegrade. Instead, it lasts forever and similarly sheds microplastics and nanoplastics, including during use and when discarded.

Silicone Bakeware as a Source of Human Exposure to Cyclic Siloxanes Via Inhalation and Baked Food Consumption

Hence, silicone elastomers are very different from plastics not only related to their physico chemical characteristics, but also to their manufacturing procedure.

In the case of silicone elastomers, one of the most essential criteria to determine suitability for food contact is the limit for volatile substances of 0.5% as required by the Recommendation XV. Silicones of the BfR and the French Order of November 25, 1992 on Silicone rubbers. To achieve this, it may not be sufficient to cure the starting material, post-curing may be necessary to remove or reduce volatile impurities or by-products.

Chemical hazards of silicone tools arise from the presence in the finished product of various volatile compounds, either used as starting materials or formed as byproducts during the curing process.

Silicone bakeware has become a kitchen staple for its flexibility and nonstick surface, yet little is known about how much of its chemical ingredients migrate into food or the air when heated. … Scientists at Health Canada set out to fill that gap by measuring how cyclic siloxanes, chemical compounds that can remain as residual substances in silicone baking forms after the manufacturing process, behave during typical baking conditions.

While there is some reason to believe that silicone will not form microplastics, the evidence is still very limited for the type of silicone rubber typically used in household products.