How long should meat be steamed for?
There are charts for when bacteria and parasites die. You will just have to check the internal temperature of the meat with a thermometer. Once it has reached the minimal temperature which makes you feel safe, you can remove it from the heat. It doesn't matter if you are steaming or using any other method. 

This is a safety-oriented chart from Jeff Potter's book Cooking for Geeks. 



And this is a detailed protein chart from McGee's On food and cooking