I was researching a meeting turned riot mentioned in Marie Ganz's memoir, Rebels: Into Anarchy and Out Again, that occurred in 1914. This isn't directly associated with the food riots but gives a nice glimpse into the political temperature of the time.
A google of some of the name mentioned by Marie garnered this article from the NYTimes: I.W.W. ARMY RIOTS IN COOPER ONION; Host of 300 Invades Socialist Symposium on Problem of the Unemployed. Then, thanks to the magic of Flickr, I stumbled upon some great photos. I was searching because Marie talks about the lights going out at the meeting, followed by bright flashes that illuminated the room. She thought it was a bomb, but realized that it was reporters taking photos.
I was hoping for those actual photos but found these again. A date is not attached to the photos, but the clothing indicates that it's the right time period. Here is a group of people gathered for a strike vote. In 1914 there were numerous strikes in the garment industry.
Here is a photo of a strike vote. I love seeing these women vote! If this photo is indeed from 1914, it must have been so exciting since women did not gain the right to vote until 1919!