www.huffingtonpost.com - October 5th, 2012
Have you ever noticed that the USDA recommends that steaks and roasts be cooked to 145° while ground beef should be cooked to 160°? Have you ever wondered why there is a difference? After all, beef is beef -- right?
Actually there is a very good reason for the difference. While meat starts out sterile, it can become contaminated with bacteria -- like E. coli O157:H7 -- when it isn't handled properly during slaughtering or processing, and once contaminated, the only thing that will kill the bacteria is heat. With intact cuts of meat -- like steaks and roasts -- that contamination will be on the surface, not on the inside. Pathogens on the surface are much easier to kill, after all, the outside of the meat heats up much faster than the inside does, so the recommended temperature can be lower. However, with non-intact meat -- like ground beef -- surface bacteria can be moved moved or "translocated" to the inside of the meat where it is harder to kill, so a higher temperature is required. Sounds pretty straightforward, right? Intact meat gets cooked to a lower temperature of 145° and non-intact meat gets cooked to 160°.
Unfortunately, steaks and roasts are often not as they seem.
So, when is a steak not a steak and a roast not a roast? As soon as its surface has been pierced, a steak or roast becomes a non-intact cut of meat and should be cooked to a higher temperature. Many of us grew up learning to make our steaks and roasts juicer and more flavorful by piercing them with a fork and letting them sit in a marinade for a while. Now, you may not be fully aware of it, but stabbing the meat created a "hide-out" for bacteria like E. coli O157:H7. And it means that the pierced steak or roast should be cooked differently. Now, assuming that you know about the increased risk of illness, you can make an informed choice about how well you want to cook that steak or roast. But what happens when you don't know that the steak or roast you have just bought or been served was already tenderized? How do you make an informed choice then?