After the disaster, there has been a scarcity of food none bar. sembra naturale?

The expression "bar none" has to be used with a superlative. For example:
She is the best student in our school, bar none.
He is the best cook in the world, bar none.
This is, bar none, the worst cake I have ever eaten.

If I had to reword your sentence, I might say:
After the disaster, there was a scarcity of food the likes of which I had never been seen before, bar none.

However, the use of the expression "bar none" in such a sentence feels very awkward. I would rather use simpler sentences such as:
After the disaster, there was a severe food shortage.
After the disaster, there was a terrible food shortage.