Nobody has answered you so far. It's probably because we all feel ill-qualified to answer. I'm ill-qualified too. As an engineer though I like to kid myself and think of myself at times as a practical scientist!
A virus is not a living organism, and it doesn't multiply and grow on 'things'. A virus loses its potency or viability the longer it is outside the wonderful environment of the human (or whatever living host it likes).
So it likes moisture. If it's warm then it will have less moisture and deteriorate quicker. Labs store viruses in freezers. Hopefully, not next to their ice creams.
You can't see a virus even with the best optical microscope in the world. It's miniscule. It can only be viewed indirectly by a scanning electron microscope.
So let's think for a minute it you can transfer a virus from one surface to the next by objects touching each other.
We could imagine that if we had two hard plastics next to each other, entirely flat, then the surface finish could be excellent and uniform and there could be opportunity there for a miniscule thing to transfer across.
When you then start looking at other material, like soft plastics with creases the the contact area at any one time is much reduced. Also if you think of how miniscule a virus is, it only has to be on an item that has even the slightest amount of texture (even texture invisible to the human eye) for it to be almost completely lost in this texture.
It's a bit like if we lowered you gently into a rainforest. If we imagine you are the virus, and the rainforest is the texture of the material. If we then got a massive piece of cloth and lowered it on the roof of the rainforest and then removed it to see if you were then stuck on it, then we'd be unlikely to find you on that cloth.
The other thing worth bearing in mind is that it is believed that the severity of Covid-19 in individuals is related to the 'viral load' they get. So if you get a great big dose of it off something or somebody then it could hit you hard. If you get a tiny viral load then your body is much more likely to be able to fend it off.
So if we think of some shopping. There could be a proper good dose of a virus if somebody has coughed or sneezed into your bag or salivated all over your huge bar of chocolate that you've treated yourself to. That's not very likely to have happened though. Yes there could be a transfer of the virus onto the shopping, and that's why it's a good idea to think it through and quarantine items if possible.
It's a bit of a balance though I find. We have "click and collect". We normally get our email that it's been prepared and picked early in the morning, around 7am. We then collect it in the afternoon. So in that time items in the bags have already had some seven hours quarantine before we go to Asda to collect. I pack the car myself, and when we get home we bring the shopping into the hallway. I put perishables straight in the fridge or freezer. I accept the risk there could be a virus on them. I then wash my hands again, and then take out all the non-perishables out of their bags and space them apart in the hallway. This should dry out any virus. I then wash my hands again. We don't touch the items in the hallway until the following day.
Those are my thoughts on it. There is probably a better way of doing it, but it is a balance of risk. The fact that we do "click and collect" has probably reduced our risk massively before any other considerations.
I'll throw this thought-grenade in as a closing remark:
Perhaps getting a little tiny dose of the virus wouldn't be so bad after all?
Trystan
