A big fat bullet instead of a comma wouldn't cost much space, but I don't think I've seen it used. People are perhaps scared of innovating when there are legal requirements that they haven't referred to recently, while they are fairly confident that what they've always done is compatible with the rules.

By the way, what is it with a large proportion of labels containing either an asterisk but no footnote, or a footnote but no asterisk in the text for it to refer to? I suppose it tells us something about the workflow they use for producing these labels.

I think it's less about fear of innovation and more about other constraints like space and readability.

A comma in most condensed sans serif collections like those used for nutrition labels (Helvetica, Univers, et al.) takes up less space and is more readable than a bullet or other glyph.

Here's a quick example using Roboto Condensed and the ingredients for Fruit Loops. The bullets are longer or harder to read. (Using Roboto Condensed because it's free so others can test with it and it's comparable to Helvetica/Univers).

Sample: https://i.imgur.com/HeYTdWr.png

Check out the ingredient list for RxBars!

https://www.rxbar.com/shop.html

You often find ingredients formatted as a table on bottled water labels. For example, https://strugglingthroughtofitness.files.wordpress.com/2015/....

That's not the ingredients that's the nutritional information. The ingredients list for that bottle would be:

Ingredients: Water