noun
foreign substance; contaminant; impurity
Refers to an unwanted object or substance that has gotten mixed into something else, often used in technical or quality-control contexts.
食品に混入物が見つかったため、回収された。
The food was recalled because a foreign substance was found in it.
この粉末には微細な混入物が含まれている可能性がある。
This powder may contain fine impurities.