I received this comment on the site recently:
“I learned this weekend that the wax inside of takeout and to go products can be lined with wax that may contain gluten. Found this to be disturbing but very helpful in explaining some of my symptoms the last couple of weeks. What about parchment paper or wax paper? are they safe or not?”
Well, you know what I’m going to ask. Where did you “learn” this?
Was it from a reliable source, or was it something you “just heard”?
I’m not trying to be difficult, Honey Bunch. It’s a legitimate question.
You know how I feel about misinformation. In the case of take away containers for food, I believe you received some.
Here in the USA, most take away foods are packaged in Styrofoam (called large or small “clamshell” containers) or coated paperboard boxes (either rectangular with a separate lid or the classic Chinese takeout box, called an Oyster Pail Box).
It is the coated paperboard our sweet reader questions.
Of course, as always, I’ll serve up a bit more info than asked for. You can’t go wrong with an extra helping of good information.
Note: I’m not judging these as “good” or “bad” in terms of environmental impact. That’s a different article for another writer to tackle. I’m simply examining what is most often used and whether or not it poses a risk of gluten contamination.
Styrofoam is the trademark name (owned by Dow Chemical) for polystyrene foam. The type used in food containers is made from XPS foam (expanded , not extruded, polystyrene). It is approximately 98% air and 2% petroleum-derived chemicals (hydrocarbons, not hydrofluorocarbons, in case you’re curious.)
While these containers pose an environmental hazard (due to their lack of biodegradability), there is no risk of gluten contamination. (While not gluten-related, I must mention the potential hazard associated with re-heating and overheating these containers. I do not recommend reheating food in these.)
Oyster Pail Box (aka the Chinese Takeout Box) and other Paperboard Boxes
The Chinese takeout container, with Japanese-influenced origami construction, is a very American invention.
It’s been around since the late 1800s (no kidding!) and has seen very few changes since its inception. It led to all the convenient paperboard boxes you see in restaurants and at food bars in places like Whole Foods. (More on Whole Foods boxes in a moment.)
Today, most paperboard boxes for food storage are made from bleached sulfate paperboard with a polycoating on the inside to make the boxes grease- and leak-proof.
Now, we’re getting to our reader question. But first, I know you’re wondering about the bleached sulfate.
Bleached sulfate paperboard
Wood chips and chemicals (that’s where the sulfates come in to play) are combined and heated to break down wood fibers and bind them together.
The resulting pulp is bleached to produce a white paper product.
Chlorine, once used almost exclusively to bleach pulp, is now being replaced (by some manufacturers) with alternative bleaching agents such as chlorine dioxide, oxygen, ozone and hydrogen peroxide, due to environmental concerns.
Is it safe? Well, in terms of gluten, there is no apparent risk. I’ll leave the chemical concerns for you.
Now, on to the polycoating that makes those paperboard boxes leakproof.
Polycoating – Low-Density Polyethylene
This is really what the question was all about. (You know I can never give you part of the story and leave you asking more questions. I hope you don’t mind.)
The fact is almost all plastic-coated paper products are coated by an impregnation process (just think: mixing really well so they do not separate) using low-density polyethylene (LDPE).
LDPE is a non-biodegradable plastic (that means it is petroleum-based), recycling number 4.
LDPE is widely used in food containers like milk boxes, juice cartons, paper drinking cups, frozen food boxes, as well as in plastic paper bags, 6-pack rings, some paper plates, and yes, those paperboard take away containers are likely coated with LDPE.
Again, no risk of gluten here.
What about Eco-Friendly Take Away Boxes?
They do exist, but the truth is, most restaurants do not invest in these higher-priced containers.
If you visit the food bar at Whole Foods Markets; however, you will see various sizes of tan boxes made from a mixture of natural fibers including sugar cane pulp, cornstarch, asparagus, tapioca root and bamboo. (Is this going to raise a question about individuals with corn allergy?)
Other options exist, but keep in mind, I’m covering what we are most likely to see, not the exceptions. ;)
Now, let’s wrap up our discussion with wax paper and parchment paper.
Wax paper is coated with paraffin wax.
Paraffin is derived from petroleum (hydrocarbons, again) and undergoes a lengthy reining process to purify it for use in food-safe products like wax paper.
In terms of gluten contamination, I can find no risk that exits.
If heating food in wax paper, you may notice some wax comes off the paper. If you’re concerned about wax getting onto your food, there is technically no concern because the paraffin used is refined and purified. However, because this is a petroleum-derived product, some have concerns.
I’ll leave that up to you. (I can’t stress enough how much I do not want this to turn into a discussion about anything except gluten content of these products.)
Parchment paper, which is excellent for grease-free baking, is made from chemical treated pulp. The chemical used is usually sulfuric acid.
A similar product, Bakery Release Paper, is made in the same way but also coated, usually with silicone.
In terms of gluten, no worries here, either.
If you’re interested in more natural options for wax or parchment papers, there are unbleached paper products made from more eco-friendly products and methods.
One company I’ve used products from is If You Care. No, they aren’t paying me to tell you about them. I’m pretty sure they don’t know I exist. But they make lots of alternative products like foil, baking cups and paper baking pans which are pretty cool.
Just an FYI: their wax paper is coated with soy wax, so may not be for everyone (like me).
There are other companies producing similar goods. You’ll find them on the web.
One last point…
Our reader mentioned symptoms of gluten contamination after eating take away meals. She indicated the food containers might explain those symptoms.
Based on the facts about take away food containers I have found, that is near impossible.
I do have some ideas about likely sources of contamination and resulting symptoms:
1. Ingesting hidden gluten in an unknown ingredient.Consider ALL the ingredients included in each part of your meal. There are many, many opportunities for contamination.
2. Cross-contamination with gluten during food preparation.
3. Another food you are sensitive to and perhaps do not realize it, or do not realize it was in the meal you ate.
It is doubtful the take away containers are the culprit.
I hope this clears up another little bit of misinformation floating around.
Keep asking questions, and I’ll keep the fresh facts coming your way!