Blue cheeses like Gorgonzola, Roquefort and Stilton contain roquefortine C, a tremorgenic mycotoxin produced by the Penicillium mold used to ripen them. Dogs are especially sensitive — signs like vomiting, tremors and high fever can appear within just 15 minutes, and severe cases can progress to seizures. Unlike regular cheese, even a small amount of blue cheese is not safe for dogs.