Bleach (sodium hypochlorite) is alkaline despite the “acid” in its name and oxidizes viruses—effective on norovirus-contaminated surfaces. Some “space disinfectant” gimmicks even used it and caused chemical burns when sweat hit the chemical.

While reading up I tripped over a quirky rule: don’t use sodium hypochlorite on sesame. People once bleached black sesame to sell it as pricier “white” sesame; the ban remains, and industrial labels still say “Do not use on sesame.” The additive standards also ban sodium sulfite for the same reason. (JP source: MHLW notice, 1971-11-08)

What I dug up along the way

• Household bleach bottles didn’t show the sesame warning; an industrial product (Kenmix 4) did: “Do not use on sesame.”
• Wikipedia’s sesame entry: 99.9% of sesame used in Japan is imported; Kikai Island has sun-dried “Sesame Street” roads; “open sesame” might have a risqué origin.
• Someone on NicoNico even demoed bleaching black sesame—time-consuming but apparently profitable back then.

Norovirus disinfection reality

• A national lab report compares heat, UV, gamma, hypochlorite, alcohol, ultrasound, etc. Hypochlorite is the most accessible/effective at home. Norovirus can’t be cultured, so feline/canine calicivirus stand in for tests.
• Alcohol (even 70–80%) shows mixed results; it can work with enough contact time, but reports conflict. Good for general hygiene, not as the only norovirus killer.
• Hypochlorite works when mixed right: ~200 ppm for routine surfaces; ~1000 ppm for vomit/feces cleanup. Many city guides (e.g., Hiroshima, Shimane) publish dilution instructions—ventilate, glove up.

Related tools I noted

• Ethanol spray “Dover Pasteuriser 77”: food-safe, ~77% alcohol; great for kitchen sanitizing and even wiping glass. Not guaranteed on norovirus, and it can leave white marks on flooring.
  パストリーゼ77 スプレーヘッド付 500ml アルコールスプレー 日本製 除菌 無香料 アルコール除菌スプレー

  ドーバー酒造
• Hypochlorite spray “Wilbas” (200 ppm): fine for daily surfaces/deodorizing, slight chlorine smell.
  ウィルバス500ｍｌ(200ppm)

  クレスト
• Vomit solidifier “Outolock”: gels vomit and claims virus inactivation—handy for homes/daycares.
  嘔吐物凝固剤 オウトロック 700g 嘔吐物処理剤 徐ウイルス 消臭 除菌

  プロケミ

Use/handling reminders

• Dilute hypochlorite correctly; avoid metals/electronics (corrosion).
• For vomit cleanup, use ~1000 ppm hypochlorite plus absorbent/solidifier and dispose safely.
• Food-additive status ≠ blanket OK—check permitted uses (like the sesame ban) instead of assuming “edible means any food.”