So I love my collapsible silicone lunch box and Stasher snack bag, but I’ve also been asked loads on whether silicone is safe to use when it comes to containing or cooking food and how environmentally friendly is it exactly, so I did some intense digging and thorough research, and here is what I found!
What we make with silicone these days
Just a quick overview on what we make with silicone these days – lunchboxes, bakeware, replacement of single use ziploc bags, water bottles, milk bottle heads, cooking utensils, toys, yup toys for both kids and adults, menstrual cup, fake boobs...
What IS silicone?
Not to be mixed up with silicon with one e, or silica, even though they are all related, here is a quick chemistry lesson.
Silicon – the fourteenth element on the periodic table and one of the base materials that makes up silica
Silica – is silicon dioxide, the most abundant material in the earth's crust and most usually coming in the form of sand or quartz.
Silicone – a synthetic polymer made up of silicon, carbon, hydrogen, oxygen, and perhaps other kinds of atoms as well. Basically it is derived from silica
Silicone bakeware has received a lot of attention lately because it is highly functional: It can go from the oven to fridge to the microwave to the dishwasher and then the freezer without skipping a beat. Geez, it’s like that classmate who get all As, heads up the student council and runs a marathon for fun.
As amazing silicone is --
Is it actually safe to use?
The short answer is, it depends. To expand a little it depends mainly on the grade of silicone, the temperature you expose it to, what you use it with.
Grade and quality of silicone
For food, you should be looking at food grade silicone, a non-toxic type that doesn’t contain any chemical fillers nor byproducts. Still, not all silicone is not created equal. To reduce costs, some manufacturers add fillers to the product. Luckily there is a simple way to tell: pinch and twist a flat surface on the item. If white shows through, the product contains filler. Pure silicone does not change color when twisted.
Stasher proudly uses pure platinum silicone with no fillers and nothing from the petrochemical industry. I always bring my Stasher bag with me because it’s such a great alternative to single use ziploc bags for snacks and pastries!
Since the use of silicone in cookware is fairly new, there has not been much research into its safety for use with cooking. The good news is that little to no siloxanes (a potentially endocrine disrupting material) have been found to leach from silicone products that are not exposed to very high heat and fat. But it’s a different story when it comes to silicone exposed to high heat. In a very detailed post by Mary of Nontoxicforhealth.com (who is a retired science teacher who now shares her research on clean-living on her site!), she gathered a lot of studies done to come to the following conclusion: when exposed to high heat that is common when preparing food, silicone does leach siloxanes that are above health regulatory standards.
My interpretation. For lunchboxes, water bottles and baby products, silicone’s safe to use. Thanks to its flexibility, light weight, and the fact that it has no open pores to harbor bacteria, it allows for easy cleaning and is super convenient as a food container.
But for bakeware, I would go for other alternatives. After all, there are so many that work well and are proven to be safe such as glass and ceramics. And for cooking utensils, especially those that would come in contact with hot surfaces like a frying pan, I would opt for wood or bamboo.
What you use silicone with
Research indicates that silicones are certainly very stable, but they are not completely inert. In other words, there is possibility of leaching, but only when it comes in contact with certain stimulating solutions. For example, one study tested the release of siloxanes from silicone nipples and bakeware into milk, baby formula, and a solution of alcohol and water. Nothing was released into the milk or baby formula, but after 72 hours in the alcohol solution several siloxanes were detected. So don’t store tequila in your silicone water bottle? Just to be safe
Random note – silicone could stain, even though I have put curry in my lunchbox and it’s still fine. On Stasher’s website, they explain the potential of staining because they don’t use any toxic sealants for their bags, that’s why the silicone can sometimes stain with certain foods. The best way to avoid this is to choose a bag color that corresponds with your food.
How sustainable is silicone?
From my research, it is said on Mindbodygreen that silicone has additives derived from the petrochemical industry, but looking at this very 90s website by a Dr. Deny Kyriacos explaining how silicone is derived, nowhere do we see chemicals from the petrochemical industry added. So who is right? This goes back to the grade and quality of silicone we were talking about. Remember the pinch and twist test I mentioned? White showing through means that there are plastic fillers added -- And there are probably other chemicals a manufacturer could add to the product without an easy way for us to tell. But basically, pure, high quality food-grade silicone is not derived from the petrochemical industry – that’s why it is important to get your products from brands that are trusted and are transparent about their silicone quality.
I also want to clarify something here, even though pure silicone is derived from sand, it doesn’t mean it is as harmless as sand. Silicone is not biodegradable, and only specific recycling facilities recycle it. Some retailers though, such as Live zero Hong Kong, would take back your damaged silicone items and send them to recyclers in bulk.
Ultimately, although it is not perfect, I think silicone is a great material that allows for a lifestyle that adds less burden to our environment as it has the convenience of plastic yet it is way more durable, non-toxic and environmentally friendly, and replaces many single use plastic items.
Because it is flexible and lightweight, it allows for the creation of collapsible lunch boxes, snack bags and water bottles, making it much more convenient for us to reduce our use of single use plastics. Nowadays I always bring around a collapsible lunch box in my bag so whenever i have leftovers at dinner, I could easily just pack it away in my lunch box! I also love my Stasher bag. I really like getting pastries from local bakeries but there is just so much plastic involved, with my silicone snack bag, I can just ask them to chuck my pastry in there :D
OK in conclusion
Silicone is definitely a way more eco-friendly option to plastic. Safety-wise the good news is there is little evidence showing that silicone containers leach harmful chemicals into our food under low/room temperature use, when it’s of good quality and you don’t store martinis in them, but the questions and uncertainty are there, so it’s worth keeping a close eye on them as more research comes out.
In summary, to be safe
Use silicone products for food items in replacement of single use plastic
With cooking and baking, I would avoid silicone since there are proven alternatives that do the job just as well, such as glass or ceramics. Silicone bakeware might be safe, but why risk it! For now
As for baby products such as teethers and pacifiers, natural rubber seems to be the proven safest and most eco-friendly alternative . So although again there hasn’t been strong evidence saying silicone isn’t safe in those uses, natural rubber would seem like a good alternative. Basically if I have a kid I would use natural rubber.
Hope this was helpful!
Also feel free to do some further reading on this post by The Eco Mum, some very thorough research there referencing research studies.