Plunging in a saucepan of boiling water is probably the safest, petallus. Take it out of its bag first though. Boil for five minutes then drain in a colander and pour boiling water from the kettle over it to rinse off any excess starch.
Microwaving is not safe because of the hot/cold spots.
It's a good idea to invest in a food probe. They are quite cheap now and very useful at Christmas when our ovens are often choc-a-block. The current recommended temperature, where bacteria no longer multiply, is 75C.