7 Japanese Food Safety Tips for Bento Lunches in the Summer

7 Japanese Food Safety Tips for Bento Lunches in the Summer

Now that we’ve fully entered summer here in Kyoto, the temperatures are high and the humidity is relentless. In other words, it’s the perfect temperature for bacteria growth in bento box lunches! With the culture of safety and meticulousness in Japan though, you can be sure that there are many dependable tips on how to prevent food poisoning. Discover 7 recommendations from Japanese home chefs on how to keep your food fresh, no matter how hot the season!

We've also curated this collection of bento boxes and accessories that will help you keep things cool this summer.  

Let’s kick-start things with a basic but important tip: 

1. Thoroughly wash your bento boxes and utensils

This might come across as a no brainer, but sometimes it’s good to review the basics! To prevent any bacteria growth building up in your box or utensils, it’s critical that you wash them well (making sure not to neglect any corners or crevices) with hot water and soap after each use.  After washing, make sure you dry your bento box well with a clean cloth and store in a well-ventilated place. For extra protection, you can also use a food-safe alcohol spray on your bento box after drying. You can also use bento boxes and utensils that feature an anti-microbial coating. Discover our Antibacterial collection here.

2. Do not touch food with bare hands

If you’re used to using your hands to mold foods into different shapes for Charaben, you might have to exercise a bit of intention with this one! It’s important though to use utensils or disposable gloves as the bacteria on our hands could easily transfer to the food, and cause food to go bad. 
We recommend using chopsticks such as our cooking chopsticks or easy grip Tornado Chopsticks.

3. Make sure food is room-temperature or chilled when packing. 

This may be an annoying step if you’re packing your lunch on a busy morning,  but it's important, especially if you are using freshly cooked rice. If you close the lid of your bento on hot rice, condensation will form on the inside of the lid which can create a humid, warm environment, setting the stage for the breeding of bacteria. If you are placing hot directly into your bento, just make sure you give it some time to cool down before closing the lid. You can always get other tasks done while you wait for your bento to cool.

4. Use an ice-pack! 

Bacteria particularly grows in temperatures of 25~37℃ (77-98.6°F) and ice-packs can make a HUGE difference in keeping your bento at a safe temperature! Placing an ice-pack on top of your bento is the most effective way to keep things cool. The outside of the ice-pack might become damp so you can use a furoshiki or handkerchief to wrap it in. Want to make things even easier? Check out our Gel Cool boxes, which have nifty built-in ice pack lids!
Discover our Clear Heart Ice Pack, our Clear Star Ice Pack and Ninja Ice Pack.


5. Use insulated bags to maintain a safe temperature

This is relevant especially if you are unable to place your bento inside a refrigerator once you arrive at school/work or have a long commute in hot weather. We’ve got bags that are not only insulated but super cute, and minimalist and stylish. Already have a bag you like? You might like our insulated liner then!

6. Choose the right foods

Here are some foods we DON'T recommend including in bento boxes during hot months: 

  • Raw cut vegetables with high moisture content (the moisture that is released can encourage bacteria growth)
  • Soft-boiled eggs (as they may carry salmonella that hasn't been cooked off)
  • Soupy, stewed dishes
Raw tofu

  • Dairy products like creamy sauces or soft cheeses.

Here are some foods we DO recommend including when it's hot outside:


Deep-fried foods like Karaage (fried chicken), Ebi Fry, Tempura. These are low-in moisture and are cooked well, and so are low-risk in terms of bacteria growth. Discover our Deep Fried Foods Collection here.
  • Food that is thoroughly cooked (boiled or grilled meat, vegetables)
Antibacterial condiments and ingredients like garlic, vinegar, wasabi, ginger, and umeboshi (sour pickled plum). These foods are also great as they add some acidity and heat to your food, which helps stimulate appetites that may be flagging in the heat.

  • Furikake—this won't add extra moisture to food, so it’s a safe way to add a lot of fun flavor to your bento.

7. Trust your judgement.

Finally, if something smells, looks, or tastes a bit off/strange, don’t force yourself to finish your food! It’s always better to be safe than sorry when it comes to food poisoning.


With just a bit of ingenuity, creativity and common sense, you can definitely enjoy bento in the summer! We hope you learned something new and useful to aid you in your year-round bento adventures.

P.S Have YOU had any fiascos with bento going bad during the hotter months? Any tips of your own that you’d like to share or questions? Let us know in the comments below!

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