To provide a sterilization method capable of limiting an absorbed dose of X ray to an edible part to a reference value or lower while irradiating with electron ray enough to perform disinfection a surface of a food product including a shell or an outer coat that covers the edible part.SOLUTION: A sterilization method of this invention includes the following steps of: irradiating an egg shell 4 with electron ray EB at 80-150 kV accelerated voltage in a state where a TLD element T and a polyethylene film PEF are disposed between agar-agar CD corresponding to an edible part of a raw egg as a simulation sample and the egg shell 4 corresponding to a surface part, obtaining an emitting light amount, and obtaining a surface dose of the egg shell 4 by an RCD film dosimeter R； obtaining an X ray dose corresponding to the obtained emitting light amount from a calibration curve； obtaining an adjusted inner dose from an expression (B/A)×C, where A is the surface dose, B is the X ray dose, and C is a permissible value of the surface dose； and disinfecting Salmonella typhimurium by irradiating the raw egg with the electron ray EB at 80-150 kV accelerated voltage when the adjusted inner dose is the reference value (e.g. 0.1 Gy) or lower.SELECTED DRAWING: Figure 5【課題】可食部を覆う殻や外皮を有する食品について、その表面においては、殺菌ができる程度の電子線を照射しつつ、可食部のＸ線の吸収線量を基準値以下に抑える殺菌方法。【解決手段】生卵の模擬試料の可食部対応の寒天ＣＤと、表面部対応の卵殻４との間に、ＴＬＤ素子ＴおよびポリエチレンフィルムＰＥＦを配置した状態で、卵殻４に、８０ｋＶ～１５０ｋＶ加速電圧で電子線ＥＢを照射し、発光量を求めかつ、卵殻４の表面線量をＲＣＤフィルム線量計Ｒによりを求める。得られた上記発光量に対応するＸ線の線量を校正曲線から求める。表面線量をＡ、上記Ｘ線の線量をＢ、表面線量の許容値をＣ、とし、（Ｂ／Ａ）×Ｃの式から調整内部線量を求める。上記調整内部線量が、基準値（例えば、０．１Ｇｙ）以下の場合、８０ｋＶ～１５０ｋＶ加速電圧で、生卵に電子線ＥＢを照射し、サルモネラ菌を殺菌する。【選択図】図５
