PROBLEM TO BE SOLVED: To provide a method of producing a rice product preservable for a long time without causing deterioration of color tone and edible even when water or a cooking tool is unavailable.SOLUTION: A method of producing a rice product of this invention comprises: an immersion step (S2) of immersing rice in water and a food additive/acidulant preparation； a rice-cooking step (S3) of cooking the water containing the immersion-processed rice and the food additive/acidulant preparation； an enzyme adding step (S4) of adding a predetermined amount of an enzyme preparation to the rice in a state where the cooking-processed rice is kept at a predetermined temperature； a sealing step (S5) of placing the enzyme-adding-processed rice containing the enzyme preparation in a heat-resistant tray and sealing the rice； an aging step (S6) of aging the sealing-processed rice in the heat-resistant tray under a predetermined temperature condition for a predetermined time； and a sterilization step (S7) of heating the aging-processed rice in the heat-resistant tray for a predetermined time in a state where a temperature at a center of the rice is kept at a predetermined temperature.SELECTED DRAWING: Figure 1【課題】長期保存が可能で、色味などが損なわれず、水や加熱器具が確保できない場合であっても、食することが可能な米飯の製造を可能にする。【解決手段】水及び食品添加物酸味料製剤に米を浸漬させる浸漬工程（Ｓ２）と、浸漬工程を終えた米及び食品添加物酸味料製剤を含む水を炊飯する炊飯工程（Ｓ３）と、炊飯工程を終えた米飯を所定温度に保った状態で米飯に対して所定量の酵素製剤を添加する酵素添加工程（Ｓ４）と、酵素添加工程を終えて酵素製剤を含む米飯を耐熱トレーに入れて密閉する密閉工程（Ｓ５）と、密閉工程を終えて密閉された耐熱トレー内にある米飯を所定温度条件下で一定時間保存して熟成させる熟成工程（Ｓ６）と、熟成工程を終えた耐熱トレー内の米飯を、当該米飯の中心の温度を所定温度に保った状態で所定時間だけ加熱する滅菌工程（Ｓ７）と、を備える米飯の製造方法を実施する。【選択図】図１
