Description of the problem:

It looks like McDonald's ketchup has a5 and a7 on the top of the package

So far, I've only seen these two kinds of ketchups

I heard from a friend of mine that it stands for acidity and sweetness and so on

I don't know if there is any one who has a more detailed explanation of this or something like this

Analysis:

A1 is the lightest, A12 is the most acidic, and A12 is the most acidic. p>

A1 is the lightest, A12 is the most acidic.

A7 is slightly more acidic than A5.