I made a batch of yogurt that went poorly. I use a Salton yogurt machine which uses a #5 plastic bucket. If this were beer, the recipe would call for baking the container to ensure that all the past microbes are dead. Obviously that won't work for a #5 plastic bucket.
It's already been through a dishwashing machine, so hot water and soap have been covered.
What other means are there for ensuring that the bacteria from the last batch don't show up in the next batch?