It happens.
My suggestion would be to hold the dish away from the direction of your face when walking and to hold your breath (or simply breathe through your mouth) while filling the dish and putting the dish down. (When breathing through your nose, you smell it. When breathing through your mouth, you don't really smell it.)
Example: Pull the can of cat food from the pantry. Open the can with a can opener (while looking away). Pour the food in the dish (while holding your breath). Hold the dish with your right hand to your right side (or behind) while walking. Place the dish down (while holding your breath).
If you have some wind or air flow, be sure your face isn't downwind from the dish. (If holding the dish to your right puts you downwind from the dish, hold it to your left instead.)