A few weeks ago the news came out of an outbreak of salmonella that was being traced to sushi, spicy tuna rolls in particular. The cases were wide spread, covering about 20 states from Texas to Massachusetts.
Sushi seemed like a strange vector. I was under the impression that it is meticulously made locally, from especially good quality fish. But...
Apparently tuna bones are scraped in much the same way as beef bones for the "pink slime" product, and distributed from a central location, and a fair amount of spicy tuna roll is made with this. No word on whether ammonia is involved.
(editied to correct the URL)