It's not mandated. You are wrong. Otherwise every restaurant serving a hamburger would have to be shut down.
The FDA has charts that simplify and explain how heat and time will kill pathogens and result in safe food. This is information meant for consumers, not restaurants, which have way different requirements that are meant to produce safe operating and serving environments, so that you don't have to rely on overcooking your meat to ensure food safety. Bringing unground beef to 145 is ONE of those values, but the temp changes based on type of food and the FDA is also open that there are other ways to make sure your food is safe and that lower temps for longer are plenty sufficient.
Restaurants then have a bit of fine print on their menu or somewhere that says "Eating raw or undercooked meat/eggs/shellfish can cause illness" and you can then order an undercooked food item.
And it wouldn't surprise me to see this requirement widely ignored. A cook could easily know to cook to the required temperature when the health inspector is watching and it's very difficult to do a surprise inspection even if they wanted to.
I fully admit I was wrong to say the FDA mandated this, but my larger point is still broadly true.
I have no experience with this subject, but I don't think hot food needing to be "held" at 135°F has any implications regarding the cooking temperature. The document you linked seems to be forbidding holding TCS food below 135°F for more than 4 hours.
One factor that further complicates the medium-rare burger issue is the fact that serving undercooked meat contaminated with E. coli is technically illegal under federal law. Even if a consumer orders their burger medium-rare, the restaurant is breaking the law if that burger happens to have E. coli in it. -- https://www.foodsafetynews.com/2014/06/rare-burgers/#:~:text....
"The federal food code allows restaurants to serve undercooked burgers as long as they have a clear written warning, such as a statement on the menu, regarding the dangers of eating raw or undercooked meat. "
That's as plain as day that there is no mandate to serve steak/burger at the 145 (for steak) or 165 (for ground beef) recommended internal temps. I wish that article cited its sources for the claims it makes. It's possible that the actual law prohibits knowingly serving contaminated beef, instead of it just happening due to supplier contamination.
That was in 1993, so maybe the "illegal to serve beef with e. coli" is from newer legislation but notice Jack in the Box was not put on trial for any federal crimes.
My reading of the article is that it's legal to serve undercooked beef as long as (a) you warn the customer and (b) it doesn't happen to contain E. coli. But since you can't ensure (b) you may be breaking the law without realizing it.
The FDA has charts that simplify and explain how heat and time will kill pathogens and result in safe food. This is information meant for consumers, not restaurants, which have way different requirements that are meant to produce safe operating and serving environments, so that you don't have to rely on overcooking your meat to ensure food safety. Bringing unground beef to 145 is ONE of those values, but the temp changes based on type of food and the FDA is also open that there are other ways to make sure your food is safe and that lower temps for longer are plenty sufficient.
Restaurants then have a bit of fine print on their menu or somewhere that says "Eating raw or undercooked meat/eggs/shellfish can cause illness" and you can then order an undercooked food item.