Value Village ／ Food & living
This answer is a draft. It stays unpublished until legal review and source verification are complete.
Microwave ovens are in kitchens all over the world. What is unusual in Japan is that the number of accidents, and their causes, are recorded by public bodies. Those records show where the risk really lies.
[Verify] The figures are based on a NITE press release (27 February 2020) and a National Consumer Affairs Center announcement (25 March 2026). Check the original text before publication.
A microwave heats by agitating the water in the food, so the wetter parts heat faster. Stir part-way through, or change the position of the food — that alone reduces uneven heating.
Both raw eggs and boiled eggs burst when heated, because the pressure inside rises. NITE has published a warning poster about it. Moreover, an egg that did not burst inside the oven can burst after you take it out, so if you have heated one by mistake, leave it alone until it has cooled down.
Sealing tightly can raise the pressure inside. Lay the film on loosely — that is the basic rule.
Heating something with very little moisture can cause it to catch fire. The smaller the amount, the more care is needed. NITE has also warned about accidents from "lazy cooking" (ずぼら調理, *zubora chōri* — careless shortcut cooking) (September 2024).
Under-heated food can cause food poisoning. The Ministry of Health, Labour and Welfare's guide figure for preventing food poisoning is a core temperature of 75°C for at least one minute.
Metal and some plastics cannot be used. Always check the markings on the container (in Japan, look for 電子レンジ対応 or 電子レンジ可, meaning "microwave-safe").
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https://www.nite.go.jp/jiko/chuikanki/press/2019fy/prs200227.html
https://www.nite.go.jp/jiko/chuikanki/poster/kaden/20022701.html
https://www.kokusen.go.jp/news/data/n-20260325_1.html
⚠️ Editorial note: the source URLs above were identified by search. Our working environment cannot reach go.jp domains, so the contents have not been checked against the text. Verify every source before publication and record who checked it and when.
What we share here are ideas and everyday practices passed down among people living in Japan, together with general information drawn from public sources. They are not official recommendations, and they are not professional instruction. Practices vary between households and regions.
This is general information. Results vary from person to person and depend on your own conditions and surroundings.
Please decide for yourself, using your own judgement, whether any of this suits your situation. We cannot accept responsibility for any damage, loss or injury arising from following this article.
Some ingredients need thorough cooking. Eat raw only foods that are sold for raw consumption. If you have allergies, check the ingredients.
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