Columbo complains about the 'clams' he ate the evening before - and is offered 'vongele' by Rod Steiger. This is a direct reference to Rod Steiger's comments in "W C Fields & Me". He always blames 'bad clams' for leaving any production featuring Charlie Chaplin.
Although Columbo has spoken Italian in several episodes prior to this one, he claims to have never learned the language. As such, it possible that Columbo makes up a new backstory depending on the suspect that he is speaking to.