Subway, for its part, has categorically denied the allegations. “There simply is no truth to the allegations in the complaint that was filed in California,” a spokeswoman wrote in an email to The New York Times. “Subway delivers 100 percent cooked tuna to its restaurants, which is mixed with mayonnaise and used in freshly made sandwiches, wraps and salads that are served to and enjoyed by our guests.” From a reporter’s perspective, however, the case bore further investigation — a deep dive, if you will. So, I procured more than 60 inches worth of Subway tuna sandwiches. I removed and froze the tuna meat, then shipped it across the country to a commercial food testing lab. I spent weeks chatting with tuna experts. I waited, and waited, until the lab results came back. Here’s what I found.