whakapirau
1. (verb) to turn bad, rot, decay, curdle, decompose, spoil.
He hapū kē nō reira ēnei ngārara. He maha aua momo e whakakawa nei, e whakapirau nei i te miraka (TTT 1/10/1927:698). / These bacteria are from a different strain. There are many types that make the milk go sour and curdle.
Synonyms: kurupopo, kurupōpopo, pirau, hanehane, koropungapunga