A vented plastic bag is adapted for containing a powdery product. The plastic bag includes a plurality of walls joined together and formed of a flexible plastic material. The walls define a fill opening for receiving the powdery product into the plastic bag. At least one of the bag walls defines a ventilation zone including a plurality of spaced-apart perforations. A filter medium overlies the ventilation zone and covers the plurality of perforations to substantially capture and retain the powdery product within the plastic bag during fill and ventilation.