noun, noun or participle which takes 'suru', transitive verb, intransitive verb
mixing in; contamination; adulteration
Refers to something unwanted or foreign being mixed into a substance, group, or process. Often used in contexts like food safety, product defects, or security. Can be used both transitively (someone mixes something in) and intransitively (something gets mixed in).
製品に異物が混入していた。
A foreign object had gotten mixed into the product.
食品への異物混入は重大な問題だ。
Contamination of food with foreign matter is a serious problem.