What stage of cooking chicken to use milk cream?

I originally purchased packaged fresh cream to make butter chicken, but then cooked a normal chicken curry in a pressure cooker and after it cooled, added around 200ml of the cream to it. But after one and a half days in the fridge, the chicken curry got spoilt (could make out from the smell). I assume this happened due to bacteria in the cream.

I kept the remaining cream in the freezer and plan to add it to some freshly purchased chicken before closing the pressure cooker lid to start cooking. I'm worried that the cream will curdle. So what is the general rule of thumb when using milk, cream or even coconut milk to thicken the gravy? At what stage of the cooking can it be added and does it need to be heated before adding? Can the curdling really be prevented? I've added milk while making mixed vegetable curry in a pressure cooker, but couldn't make out if the milk curdled.