What are Japanese plastic bento boxes made of? Are they BPA-free?

[I’ve substantially updated this article recently to answer some emailed questions about bento accessories and so on, so here it is again for your reading pleasure. Originally posted in August 2008.]

I recently got an email from a Just Bento reader concerning the plastic used to make bento boxes. She was concerned, since she couldn’t read the Japanese writing on the packaging. I’m sure a lot of other readers have similar concerns, especially given recent scares reported in the media about plastic containers leaching chemicals into food and beverages. Keeping in mind that I am not a scientist or expert, just a concerned consumer just like you, here’s what I’ve been able to find out by doing some research on various Japanese as well as English-language web sites.

Bento boxes from Japanese manufacturers

The parts of plastic bento boxes that touch food from known Japanese manufacturers are generally manufactured using three types of plastic: polyethylene terephthalate (PET), polypropylene (PP), or a compound of PET and acrylonitrile butadiene styrene (ABS) called PET-A. A common practice is to use PP or PET-A for the bento box body and outer lid, and polyethelene for the flexible inner lids, or the main lids on small side boxes.

For example, the cheaper bento boxes made by Nakano Co. (manufactured in China), which includes popular brands like Puti Fresh, Lube Sheep and Clickety-Clack that are sold at Daiso and similar ‘100-yen’ stores (previously), are made of PP. According to The Green Guide ( a site that is owned and operated by National Geographic), PP is a safe plastic, though it’s not very recyclable.

Higher end plastic bento boxes such as the very popular ones models made by Hakoya aka Tatsumiya Shikki or Yellow Studio (mostly manufactured in Japan, some accessories manufactured in China), use mostly PET or PET-A. (Hakoya also uses other plastics on parts of their boxes that aren’t in direct contact with food.) According to The Green Guide list, the main objection against PET seems to be the porous nature of the plastic, so it’s not recommended to re-use thin PET water bottles. However, from reading some Japanese reports, PET-A in particular seems to be regarded favorably as a recyclable yet food-safe plastic. In practice, I do find that my Hakoya and Yellow Studio bento boxes are easier to keep clean and of a better finish than my Lube Sheep boxes. (Update: As of late 2009-early 2010 I’ve stopped using any of my Lube Sheep boxes…not because of safety concerns, but just because they do tend to get a bit beat-up looking with continuous use. Well what can you expect from boxes that retail for 100-200 yen ($1-2 or so) in Japan?)

What about BPA?

The substance that has generated the most controversy and concern in recent years when it comes to plastic food containers is bisphenol-A, or BPA. This exists in polycarbonate, a clear plastic that is used for some water bottles, as liners in metal cans, and so on. None of the major Japanese bento box manufacturers use polycarbonate in parts of their plastic bento boxes, water bottles and so on that touch food. (I have seen a few thermal mugs that use polycarbonate on the exterior parts that do not come into contact with the liquid.) It may be interesting to note that the Japanese canning industry began to voluntarily cut down on the use of BPA as can liners as early as 1998 (a decade before BPA even began to be talked about the the United States for example), and have been using other plastics since. (see.)

So in a nutshell, any bento box from a reputable Japanese maker should be perfectly safe. Generally speaking, food safety regulations in Japan are just as strict as they are in North America or Europe.

However, you should always heed the directions about whether or not a box is microwave-safe/dishwasher-safe or not. If you are not sure and are concerned, ask the seller of your bento box, or just don’t put it in the microwave. Needless to say, plastic is not oven or stovetop safe!

(Studies on the safety or not of BPA, especially for adults, still seem to be inconclusive. As with any other health related news, try to read as many reputable studies as you can and keep an open mind.)

Bento accessories (picks, inner cups, baran, etc.)

Most rigid plastic bento accessories made by companies like Torune such as picks, are made of ABS and/or polystyrene. Many reusable inner cups are made of silicone. Flexible plastic items such as baran (dividers, like ‘sushi grass’) made by Torune are made of PET.

Note that most of these accessories (except for silicone cups) are not microwave safe, so use your cute little picks and such for bentos that you don’t intend to nuke, or else take them out before doing so.

Nori cutters made by Arnest (the Niko Niko Punch line) and Kaijirushi (the Chuboos line), are made of ABS (the body) and zinc or a zinc alloy (the cutting parts). I do not have information on repurposed cutters that are meant for use on paper and other non-food products. If you’re really concerned about safety you may want to avoid using these on food.

Food cutters by Arnest (e.g. the Kyarappa line) are made of polystyrene.

What some popular non-Japanese manufacturers use:

  • Rubbermaid: A useful page on their website with a list of which of their products contain BPA (i.e. are made of polycarbonate) and which don’t. (Generally speaking their clear plastic containers contain BPA.)
  • Lock & Lock food containers (I don’t know about their non-food containers): PP
  • Fit & Fresh: PP
  • Ikea (their 365+ line in any case): polypropylene carbonate (PP-C)
  • Tupperware (their food containers): low density polyethylene (LDPE) or PP

Plastics to avoid

It might be tempting to re-use takeout containers, but again according to The Green Guide, that may not be such a good idea (this link is now broken, and their internal search leads back to their home page. grr). In essence you should not be re-using plastic containers that are not meant for multiple use, like takeout boxes and such, if you’re concerned about plastic safety.

Plastic alternatives?

The most practical alternative to plastic for bento boxes is probably stainless steel. See Stainless steel bento boxes. My favorite model of stainless steel bento box has a silicone sealing element around the inner rim of the lid; this is quite acceptable to me as a ‘green’ bento box, and makes it very practical. There are also 100% stainless steel bento boxes or lunch boxes, such as those from Lunchbots (their orange-lid model is a good size for a bento box). Beware of packing any moist food in them since the lids are not leak-resistant.

Stainless steel bento boxes are generally more expensive than plastic, but should last a lot longer with proper care.

A very stylish though rather high maintenance alternative to plastic is wood. Traditionally bento boxes were made of wood, either untreated or coated with lacquer. Wooden bento boxes are wonderful, but need to be handwashed carefully and dried with a soft cloth immediately after washing. A famous type of wooden box is the Magewappa, made of uncoated bent Japanese cedar.

This is my personal opinion, but when it comes to wooden bento boxes, you really get what you pay for. Avoid cheap wooden boxes - these usually have a rough finish, inferior workmanship, and are generally rather nasty. Expect to pay at least $40-50 or more for a good wooden bento box. A genuine Magewappa bento box will cost you at least 6,500 yen (around $70) and on up from reputable stores in Japan. On the other hand, a high quality wooden bento box will last for years with proper care.

See also

(Update added 1/09: All of the links in this article to The Green Guide site are broken because they have changed them all apparently without proper redirects. What’s worse, their internal search results lead right back to the home page too. As a web developer myself I have to say this is so very lame. Anyway, once you get to their site (all links just go to their new front page) you can look around for the appropriate information. This page regarding Bisphenol-A (BPA) is current, as of now, unless they change things around yet again.)

(Update added 2/10: Added link to Rubbermaid BPA page; added bento accessory information and plastic alternatives section.)

For more bento recipes, ideas and tips, subscribe to Just Bento via your newsreader or by email (more about subscriptions).

And visit our sister site, Just Hungry for great Japanese home recipes and more.

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Plastics

This is superbly informative! Thank you for posting!

Re: Plastics

http://www.thegreenguide.com/buying-guide/plastic-containers

"#6 PS: Polystyrene-foam cups and clear plastic take-out containers can leach styrene, a possible human carcinogen, into food. "

Re: Plastics

it is also important to understand that Chinese manufacturers have been caught in numerous occasions in other industries breaking rules which in North America and Europe would consider unsafe.

Yamaha fined a Chinese manufacturer for selling a chinese copy of a yamaha as a yamaha.
Lead has been found in products made toy manufacturing plants.
Cheap alloys used in bicycles.
Chemicals sprayed in produce grown in China to make them "look" fresh.
You should be weary if it's made in China.

BPA is plastics are dangerous over 400deg. Other than that your biggest concern is LEAD.

are nori punches "food safe"?

Along similar lines, I was wondering if nori punches (i.e., usually just paper punches from the craft store) are really safe to use. Anyone know? The cutting plate seems to be made of some soft, heavy metal. Could it be lead? I sure hope not, they’re awfully cute.

The nori punches

Edit: I’ve looked into this and answered it in the post.

Re: What are Japanese plastic bento boxes made of?

Thanks for such an informative article.

(I just realised I sometimes microwave my Lube Sheep box, hope this doesn't make it unsafe...)

I am also interested in the ethical nature of bento producers, where the items are made (like in china) and what their work/business practices are like for factory workers. Do you know of anywhere that has information about this? Even one which could recommend popular brands that are more ethical?

Thanks!

Re: What are Japanese plastic bento boxes made of?

Hi Kate,

There is a blog post by Bento&co's Thomas about a factory visit to the Hakoya brand manufacturer (Tatsumiya Shikki). The post is in French, but there are lots of photos - it shows that they produce their boxes in Japan in Ishikawa prefecture, by skilled workers using precision engineering methods. So I guess it's pretty safe to say they are an ethical company as far as work practices go. The same should apply for any box that is actually manufactured in Japan.

I have not heard anything bad per se said about bento boxes manufactured in China ( like the Lube Sheep boxes) by Japanese companies but I know very little really about Chinese manufacturing practices. In any case remember that Lube Sheep sells for 100-200 yen in shops in Japan, while Hakoya sells for 10x that price....

Re: What are Japanese plastic bento boxes made of? Are they ...

Thanks so much for this information! I bought a sweet little Hakoya bento box at an H Mart near me and have been wondering ever since about the plastic content. I try not to use any plastic in the microwave, so sometimes my bento is used to carry the food, then it gets transferred to a ceramic bowl at work before heating. I've learned so much about bento by reading your posts. Thank you, and I look forward to reading more. Jeni

Re: What are Japanese plastic bento boxes made of? Are they ...

Thank you for your usefull information. I've just been wondering if you don't use your Obento like all the time, would it still be safe? Also how long usually those plastic Obento boxes can be used? Like 10 times of usage or more, then we need to buy a new one.
Sencierly, Yoka

Re: What are Japanese plastic bento boxes made of? Are they ...

Bento boxes from reputable sources that are made to be used regularly, can be used over and over indefinitely...just like Tupperware for example. Much more than 10 times, that's for sure! And I've never heard problems with them being unsafe after a period of disuser.

Re: What are Japanese plastic bento boxes made of? Are they ...

Though it may not be very stylish or cute, I prefer using Pyrex instead of plastic. It can be quite big and heavy but at least, I don't have to worry about microwave some of my oily lunch or lunch with pasta sauce. With pasta sauce, it's quite difficult to remove the stain left on the plastic lunch box after the food is reheated.

Re: What are Japanese plastic bento boxes made of? Are they ...

I definitely accidentally microwaved the lids on my Daiso Lovely :( Its kinda bent it a little. Hope it also doesn't make in unsafe! I was just slightly annoyed that I had done something so silly and bent it a little out of shape. Now I am worried about poisoning myself!

Re: What are Japanese plastic bento boxes made of? Are they ...

thank you for this information, I am starting a blog as I have just descovered Bento Boxes. I LOVE them, and am looking for all the information I can find. I too was concerned about the plastic used in making them.

Re: What are Japanese plastic bento boxes made of? Are they ...

I was given a Pack Mate bento box by Inomata - is that BPA free?

Re: What are Japanese plastic bento boxes made of? Are they ...

Hi Maki, thanks for the informative article. Another alternative is glass containers. Maybe not ideal for children, but I love them because I don't like storing food in plastic & they can microwaved no problem. I've been using rectangular Pyrex containers that are the perfect size for my lunches (http://www.pyrexware.com/index.asp?pageId=14&CatID=380&SubCatID=398&upc=...)

Re: What are Japanese plastic bento boxes made of? Are they ...

Just what I was looking for! Thanks for the helpful information. :)

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