Unless it was on some dust, that risk of airborne seems unlikely. Covid spiky shape you have seen is useful for it to attach to surfaces (although it doesn't have a brain to make decisions so it's just circumstantial) which makes it so easily transmitted. Lots of research needs to be done so we have to wait for the experts to provide definitive answers to questions like this. Until then, multiple scientists are checking out their theories. No one knows what the minimum viral load would have to be either, as far as i can tell.
The way the virus could get on something is via sneeze droplets, or aerosolized virus that floats in the air. If there had been sneeze droplets on the packaging, by the time it was in your trash it would be too late for any virus to be viable. And aerosolized virus doesn't come from pushing on packaging and having a rush of air in your face, it happens only in special circumstances (can happen when someone is in the hospital and being intubated, for example). From what I've read, even forceful sneezing doesn't have enough force to aerosolize the virus. (You could google how long the virus can live on packaging and how infectious it is after it's been sitting on paper or cardboard. But even when they find the virus when they look on surfaces, it's questionable how long it remains viable.)
The virus is so new that there are just a lot of unknowns. Other countries' experiences suggest that while Covid-19 is contagious, it is not like the most contagious illnesses (measles, for example, can spread like wildfire among people who have no protection). So, wash your hands and stay 6 feet away from others like they say, but try not to be so worried that you stress over every little thing.