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

[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 .]

For more information, please visit our website.

I recently got an 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 -early 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 (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.)

In order to help you decide which bento box is right for you (or your child), we tested a selection of highly-rated options, packing them up with a variety of lunches and transporting them in bookbags, purses, and tote bags. Each bento box was rated on its design, insulation, size, versatility, and overall value.

Bento-style meals and boxes have roots in Asian cuisines, including Chinese, Japanese, and Korean, but have since spread through the rest of the world. The main section of the box traditionally held rice or noodles, but bento boxes can be used to contain everything you need for cheese and charcuterie, party dips and spreads , on-the-go sandwiches and snacks, and more.

A bento box is simply a boxed meal with compartments separating toppings or courses. Bento is derived from a Chinese word meaning "convenient," and at its most basic, it&#;s lunch packed to be eaten on the go.

If you plan on reusing them, prolong the life of these containers by hand washing them (though they are top-rack dishwasher-safe). While they are not exceptionally long-lasting or heavy-duty, they&#;re inexpensive enough that if one gets left behind or tossed in the trash, it won&#;t feel like a major loss. Definitely check the rules in your area to make sure they can be recycled before throwing them in the recycling bin.

Featuring two compartments, they're roomy enough for a main dish and side, a nice-sized salad, or a sandwich and chips. These sets aren't entirely leakproof, so they're better suited for foods without sauces or liquids. During testing, we found that they can be used in the freezer and microwave but noted that they may be prone to cracking or melting in the microwave after a few uses.

If you're searching for a bento box that you don't have to take home and wash, these disposable containers are perfect. Ideal for days when lugging around a dirty food container isn't an option (like a school field trip or travel day in the car or on a plane), these boxes are made from BPA-free plastic and come in a pack of 15.

While this box doesn't come with utensils, there is some space to store a coordinating Monbento cutlery set right under the lid. This bento box is dishwasher, microwave, and freezer-safe to make transporting and reheating your food a breeze, as well as cleanup when you're finished. Previous versions of this lunchbox included dividers, but they have been replaced with a small food cup. Monbento also offers a variety of food containers for both liquid and solid foods, all to match the elegant designs of the classic bento lunch box.

Each bento box is constructed with two equally sized boxes, each with its own airtight lid, and a small food cup that fits into either box (great for berries, crackers, garnishes, or sauce packets). We like its slim design and slightly rubberized exterior, making it easy to hold and transport. It is more shallow than some other styles, but it easily holds a traditional bento meal of tonkatsu and shredded cabbage , rice, and tamagoyaki. The lids have a pull tab to open the vents, which let hot air escape during reheating in the microwave. We also appreciate how the bento box has a slightly grippy texture, which makes it easy to hand-carry.

Monbento has been making these incredibly attractive, French-designed, luxe bento boxes since . Each classic bento box is streamlined with a minimal look and feel but exudes softness with delicately rounded edges, a comforting color palette, and a BPA-free plastic that's soft to the touch.

This product is top-rack dishwasher-safe, which makes it a cinch to clean up any oily residue left behind by salad dressing. We wish it was insulated and could keep greens and ingredients chilled without a refrigerator, but that is only a small complaint. Available in a variety of colors, it's a great choice for anyone who wants to make salads a regular part of their lunch routine.

We packed a hefty amount of greens into the bottom section and loaded the top compartments with all of the ingredients for a Greek salad&#;vegetables stayed separate from the feta and kalamata olives, and the dressing stayed put without leaking. When it came time to eat, it was easy to top and dress the salad, and the included fork (stored in the lid) was comfortable to use, spearing greens, olives, and cherry tomatoes easily.

If you find yourself frequently packing salads to go, this bento box is uniquely designed for such a task. It features a large, 6.75-cup bottom container for greens and three upper compartments (one 10-ounce and two 5-ounce) for chopped vegetables, croutons, or whatever salad toppings your heart desires. It also includes a lidded container that nestles in the center section to hold salad dressing, so you can add it when you're ready to eat.

The latches are easy enough for kids to use, but they latch securely, so the box will stay closed until it&#;s time for lunch. If this bento box isn&#;t big enough, the larger version holds a whopping 8 cups of food, so it&#;s great for folks with big appetites, for carrying fluffy foods like green salads, or for sharing. This model can be run through the dishwasher for easy cleaning.

During testing, we filled this lunchbox with a sandwich, carrot sticks, cucumber slices, and cherry tomatoes, and used the snack pod for a serving of berries. The durable construction kept the sandwich from being crushed when the box was jostled around in a bag during transport. Since it&#;s made entirely from stainless steel, this bento box can't be used in the microwave, so it's best suited for meals that are eaten cold or at room temperature.

This stainless-steel bento box has two stacking tiers plus a lidded snack pod that can keep your sweet treats from decorating your salad. It's a smaller bento box than most of the other models we tested, but it's big enough to hold a sandwich, side, and snack&#;perfect for a kid's lunchbox . This style of bento box is not leakproof, so you won't want to use it for anything that has sauce or liquid.

While the removable dividers are adjustable, we found that they don't stay in place well enough to provide a completely airtight seal&#;which is completely fine for keeping dry foods separate, just something to be aware of. Thanks to the elastic strap and silicone seals, we didn't report any spills or leaks outside the compartments, even after using this bento box for multiple meals at home and in the office.

With removable dividers and two roomy compartments, this bento box's classic design makes it easy to customize both your meal and the container itself. We love this model for lunch because it is perfectly compact, leakproof, and includes two sauce jars. Another feature that we appreciated during testing was the wooden utensil set, which came complete with a serrated knife, fork, spoon, and chopsticks. It's easy to overlook the utensils, and many sets that come included with similar bento boxes are too small, flimsy, or otherwise unusable, but these ones are a good size and made out of sturdy wood (though keep in mind that only several of the color options come with the wooden utensils, so we can't speak for other versions).

The removable compartment tray is microwave- and dishwasher-safe, while the outer shell should be hand-washed to preserve the seal. It's available in green, purple, or blue, and there are also options with bright colors and multiple fun prints to suit any taste. We did notice after testing that the outside scratches fairly easily, which doesn't pair well with kids, but it is still a great option.

Kids will love this colorful bento box. It has five compartments that are portioned for a child&#;s appetite&#; and is designed for kids aged three to seven, but it would also make a great snack container for adults. It has rubber-coated edges and internal hinges that help make it drop-proof and sturdy enough for the most active children. It also includes a booklet with 30 recipes and meal ideas for kids . The box is leakproof and has two child-friendly latches that make it easy for small hands to open and close, but it is heavier than other options. Our testing involved packing lunch in the Bentgo box for a week and we were thrilled to find that nothing leaked at any point.

This set is top-rack dishwasher-safe, but hand washing is recommended to avoid warping the lid. The bento box holds about 38 ounces, so there&#;s plenty of space for lunch or dinner, making it a versatile box for kids and adults alike.

We loved the simplicity of its design&#;the box is leakproof and easy to open and close, making it a great choice for kids' lunches. However, it isn't leakproof between compartments, so if you have sauce or dressing, you'll want to pack it separately to prevent seepage. This model includes a fork, but we found it to be quite small and uncomfortable for an adult to hold, so you may want to invest in a full-sized silverware set instead.

If you are looking for more details, kindly visit Tongqi.

This single-layer bento box has three compartments&#;one main section for an entree, and two smaller sections for sides and/or dessert. This was large enough for an adult portion of spaghetti and meatballs, a hunk of garlic bread , and a serving of vegetables, but it would also lend itself well to a sandwich, veggie sticks, and a serving of fruit.

To clean, this box can be run through the dishwasher on the top rack. Made of thick, recyclable polypropylene, it's very sturdy and shows no dings or scratches after several uses, but isn't insulated. The bento box is also available in several colors and comes with a full set of utensils&#;a fork, knife, spoon, and set of mini chopsticks.

Each layer's lid has a gasket around the edges, ensuring the tiers are entirely leakproof. The lids also feature a vent to allow hot air to be released during reheating in the microwave. We found that the tight-fitting lids were a little difficult to open, so this set would be best for teens and adults with better grip strength.

Bento box purists will love this classically designed box, which earned the top spot on our list after testing. Sleek and minimalist, it is composed of two tiers held together with a thick elastic band; one tier has an adjustable divider and a separate lidded container for sauces or smaller food items like berries or crackers. We noted that its compact shape is surprisingly roomy, giving you plenty of space for a traditional bento lunch of rice and meat, a side of vegetables, and even a sweet treat.

Final Verdict

The Bentohaven Bento Lunch Box is an all-around good choice in terms of design, functionality, and price. It received high marks in testing for its roomy compartments and leakproof performance. Have kids? The Bentgo Kids' Lunch Box is lightweight, easy to use, and comes in 30 different patterns.

How We Tested Bento Boxes

We spent hours researching top-rated bento boxes before testing every item on this list in real-life settings. We used the bento boxes to pack lunches of all kinds, including main courses, salads, sauces, snacks, and desserts, and transport them in order to evaluate their portability and whether or not they leaked in transit. Each bento box was rated on its design, insulation, size, versatility, and overall value. We also cleaned the boxes and noted any signs of wear and tear or discoloration during the testing period. The tests included:

• Packing a typical lunch or snack assortment in the box
• Transporting the bento box
• Checking if it keeps the food hot/cold
• Cleaning the bento box (dishwasher or hand wash)

We Observed

• Adjustable dividers are key: Most bento boxes feature the same kind of rectangular, minimalist design. However, try looking for models with dividers that are adjustable and removable for your customized meal. Likewise, gaskets between compartments will help prevent spilling.
• Tight-fitting lids aren't always best: Although very snug lids may help avoid spills, they can make it difficult to open. The same goes for sauce container lids.
• Ease of cleaning is important: There are plenty of nooks and crannies that come with these customizable pieces, so opting for a bento box that's dishwasher safe is definitely a good idea.
• Utensils shouldn't be an afterthought: There's nothing worse than packing yourself a delicious lunch just to find your utensils seriously lacking. We found that several bento box sets came with flimsy and unusable utensils, which was disappointing (and often, a blatant waste of plastic).

About Our Testers

• Bernadette Machard de Gramont, a Los Angeles-based writer who specializes in global food and wine content, personally tested eight of the items on this roundup. Her work has also appeared in The Kitchn, Made Local Magazine, Food52, and Far and Wide.
• Linnea Covington, a Denver-based food writer who loves cooking and planning meals for her family, tested the Bentgo Kids Lunch Box with her 5-year-old son, who took it to school every day for a week.
• Katherine Gallagher, a commerce editor for The Spruce Eats, tested the Umami All-in-1 Bento Lunch Box with several different meals&#;including homemade sushi hand rolls.

What to Look for When Buying a Bento Box

Design

As you may expect with something that has been in use for nearly a millennia, Bento boxes and bento meals vary widely. At its most basic, a bento box is a tray with a lid (either attached or detached) for ease of transportation. Both traditional and more contemporary bento boxes can come in a variety of shapes and sizes but are generally either square or round. Bento meals also typically feature a variety of foods that are divided using trays or even separate compartments that are often stacked. Dividers can be fixed or moveable, allowing you more control over the portions. 

Materials

The first bento boxes were made from bamboo, then later lacquered boxes and wood, such as cedar. Beginning in the 20th century, other materials began to be used, starting with aluminum in the s. Today, you can still find bento boxes made from traditional materials as well as stainless steel, plastic, and glass. Single-use bento, common in Japan at convenience stores and sometimes found abroad as well, are typically made of single-use plastic or even styrofoam.

Insulation

Another change in bento boxes in the 20th century was the introduction of insulation in the design. Japanese insulated bento boxes tend to come in separate containers and resemble a Western-style lunchbox, with a thermos cup that fits into an insulated or non-insulated soft carrying case. The more common insulated option tends to be bento-inspired lunchboxes made by Western companies, often with a removable tray inside an insulated case. You can also find non-insulated bento boxes that come with an insulated carrying case. 

Capacity 

Bento boxes are designed with a single-serving meal in mind, but they can still vary in size. While there&#;s no one meal packed in a bento box, recipes and meal ideas tend to have a mix of proteins, carbs (typically rice), vegetables, and fruits. If you balance out your foods, you can typically create a filling meal, even in a smaller bento box. But if you want a big salad, for example, you may need to find a bento box specifically designed for a big pile of greens so you won't be left hungry. You can also consider how many foods you&#;re likely to want to pack: A bento box with lots of small compartments could be great if you like variety, or it could pose a problem if you typically want just a main and a side.

Lids

Early bento lids were completely separate from the base of the box and often tied up in furoshiki, a traditional Japanese wrapping cloth, to help keep it secure. Today, the tops of boxes are often more secure, with lids and seals that resemble other food containers. Tops can be held in place with clasps, airtight lids, or gaskets. Lids are also often hinged, making it easy to keep all parts of the box together. They vary in how leak- and splash-proof they are, so think about how much you&#;ll need to transport your bento box, and even how far ahead you'll want to prep your food; an airtight seal will help keep food fresher longer and will prevent food from spilling in your bag. 

Safety

Not surprisingly, before the advent of the microwave, bento meals were eaten cold. Today, like with all packed meals, it&#;s often a matter of preference. If you want to heat up meals, make sure your bento is microwave-safe. No matter your plans, ensure any plastic is BPA-free.

Maintenance

After eating out of your bento, simply wash and dry it until next time. Some bento, especially insulated models, have removable inside trays that can be washed, and the exterior is only cleaned as needed. Traditional materials, like bamboo or wood, require more care and must be hand-washed. Lacquerware can even peel and chip in the wrong environment&#;it&#;s little wonder that people opt for materials like metal and plastic when given the chance for this everyday product. 

FAQs

What is a bento box?

Bento is a single-portion meal designed to be taken to go. Of Japanese origin, today bento is popular all over Asia and, increasingly, the world. The bento box is designed to carry this meal, and is a popular storage option for lunches on the go.

What foods do you pack in a bento box? 

Originally, bento would have been fairly simple, just containing rice for a traveler. Over the centuries, bento developed to reflect trends in Japanese cooking. A bento will typically contain rice or noodles alongside a protein, like fish or pork, as well as vegetables. Other common items include tamagoyaki (a Japanese rolled omelet), potato or pasta salad, and fruit salad. 

Do bento boxes keep food warm?

No, bento boxes typically are not made to keep food warm. Unlike a thermos, most bento boxes are not fully insulated. They can, however, be stored in an insulated carrying case. 

Are bento boxes microwavable?

For most of the history of bento, the food was eaten at room temperature. With the advent of refrigerators and microwaves, many of us store food for hours before eating it at low temperatures or may just want a piping-hot meal away from home. Many bento boxes are microwave-safe, though not all. Check instructions before microwaving. 

Why Trust The Spruce Eats?

Bernadette Machard de Gramont is a Los Angeles-based writer who specializes in global food and wine content. After a two-year stint at Williams-Sonoma Headquarters in San Francisco, she now researches and tests a variety of cookware, bakeware, and wine tools, and she interviews field experts for their insight. She personally tested eight of the items on this roundup.

Marshall Bright, a freelance writer covering food and cooking for The Spruce Eats, updated this roundup. A self-taught home chef, Marshall is passionate about making home cooking approachable and fun for more people.

Want more information on Pp Bento Box? Feel free to contact us.