Well hot water will get rid of most of the bacteria. Pastuerization is based on elevating the temperature to what is it 150 degrees? Now boiling does not kill everything. For that you would need an autoclave. But I have not heard of any pathogen that boiling did not kill.

I would wash it thoroughly. Getting it clean will get ride of 99% of whatever is there. Be careful with the soap you use. Soap can bind to plastic and leach out slowly and affect the taste. So go light on it.

Rinse with hot water thoroughly.

Fill it with water to which you have added a small amout of bleach and leave over night. Bleach is on oxidizer and will kill bacteria. I would use the bleach in a pretty dilute fashion. Bleach will bind to plastic for the bad flavor also.

Fill it with water and let sit over night. That will flush out the flavors of the soap and bleach. If they are not gone, repeat the water over night until it is ok.

The above should clean it up pretty well.