How can I recognize good quality Genoa salami?
Recognizing quality entails knowing the product and the producers.  Obviously you need to taste and ask questions. The correct texture and flavor of the fat used in salumi is very important, as it is generally a very high proportion of the ingredient list (30 - 50%).

In general, if you want "authentic" salumi, I would think you want to stay clear of most of the factory-made products that we find in US grocery stores.  It seems that you have three options in the US.

You could purchase imported salumi from a specialty shop. 

You can locate smaller scale, artisan producers. Easily done on Google by searching "US artisan cured meat" or something to that effect.  There are many in the US.  Most do mail order if they are not nearby. I also find even smaller, more local producers in farmers markets.  These people generally will not be using sub-par ingredients.

Finally, you can learn to make your own. I've dabbled with this myself. While there are challenges and special conditions that need to be in place, it is certainly feasible if you are up for it. I will say that finding quality back fat is a real challenge for home hobbyists, like me, who aren't near a quality butcher or artisan hog operation...but there are ways of making it work.