pasteuriser vs pasteurizer

pasteuriser and pasteurizer both are nouns.

Word	Noun	Adjective	Verb	Adverb
pasteuriser	Yes	No	No	No
pasteurizer	Yes	No	No	No

As nouns, pasteuriser and pasteurizer are synonyms defined as:

pasteuriser and pasteurizer: an apparatus for pasteurizing substances (especially milk).

pasteuriser (noun)	pasteurizer (noun)
an apparatus for pasteurizing substances (especially milk).	an apparatus for pasteurizing substances (especially milk).