meatloaf episode
in the episode where the challenger's signature dish was meatloaf, flay said he had only made it maybe twice. there was an episode of throwdown where he challenged someone to a meatloaf throwdown and lost.
http://www.imdb.com/title/tt0993567/
so not only was he familiar with meatloaf he had made it before to compete on another show. In fact, you can get the winning recipe here:
http://www.foodnetwork.com/recipes/meatloaf-recipe1.html
and not only that, he created another meatloaf on the other series he had called boy meats grill. the recipe for that is here
http://www.foodnetwork.com/recipes/bobby-flay/roasted-vegetable-meatloaf-with-balsamic-glaze-recipe.html