• Friday, March 23, 2012

    How would you like that cooked?

    You order steak or a burger at a restaurant and the waiter or waitress asks, “how would you like that cooked?” What is your response? Well, if you are ordering a steak, there is no wrong answer to that question. HOWEVER, you should ALWAYS order hamburgers or any other ground meat dish cooked to medium, medium well, or well done. I always order mine medium well.

    Why should hamburgers be cooked to medium well, but steaks can be cooked to rare?

    Today, I visited a Family and Consumer Science Class and demonstrated to them the answer to this question with play-doh. (I had to fight the little Daughter at the Meat Counter off the play doh.) I took some pictures to share on my blog.

    When steaks are cut, there is a possibility that bacteria (disease-causing germs) could be on the surface of the steak. Steaks (and roasts, too) are whole-muscle cuts, meaning that they have been cut into serving- or cooking-size pieces, but the internal portion of the cut is still undisturbed. So, those bacteria are going to only be on the surface of the steak, and when you cook it, the surface will be the first to get hot and it will get the hottest. Any bacteria on the surface are going to be killed in the cooking process. The internal part of the meat does not have to get hot enough to kill any bacteria. So cooking steaks to rare or medium-rare is perfectly safe.

    Do you like my little play-doh steaks? The green dots are the bacteria (only on the surface). The Daughter at the Meat Counter thought they were peas.

    Ground beef is made from smaller cuts of beef that are trimmed away from the steaks and roasts. They are not lower quality or inferior in anyway other than they are too small or too tough to make good steaks are roasts. (Actually, which parts are cut into steaks and roasts and which parts are ground into hamburger is largely driven by ground beef demand. People like hamburgers.) These parts and pieces (trim) are kept in large containers and transported to the grinding room in the plant. All of these little pieces could have bacteria on their surfaces just like the steaks above. Several companies have researched different ways to treat the trim pieces to lower the bacterial count on the surface.

    Here is my play-doh trim. It’s smaller and cut into irregular pieces. The bacteria are still only on the surface.

    Here is where the difference is. The trim is ground. When meat is ground, it is pushed through a metal plate with small holes. Behind the plate, is a rotating knife that cuts the meat and allows it to be pushed through the plate.

    This is not play-doh. I actually have pictures of real meat! Yay! You can see the round strands of ground beef coming through the plate.

    Now, any of those bacteria that were on the surface of the meat are mixed up and spread all throughout the ground beef. When we make patties out of the ground beef, the bacteria could be on the surface or anywhere inside the patty.

    These are some patties we made for a research project. Real bacteria don’t have color and you can’t see them on or in your patties.
    It is easier to see the green, play-doh, bacteria mixed in with the red in my play-doh patty.
    When I tore open my little play-doh patty, the students could see the green bacteria all throughout the patty.

    So, when you cook patties, you should always cook them to 160 °F. USE A MEAT THERMOMETER. Make sure the thermometer is inserted into the middle of the patty.

    When you order hamburgers at a restaurant, ALWAYS order them to medium or greater.

    If you have other questions about food safety, I wrote a blog post about food safety in September.

    A common conversation over steak dinners with meat scientists is how we order our steaks. I order my steaks cooked to medium-rare. Why, you ask? Well, there are two main types of protein in meat that affect tenderness, connective tissue (holds it all together) and myofibrillar (causes the muscle to contract). These two proteins react differently to exposure to heat. Connective tissue (collagen) protein dissolves to gelatin when it is heated, so it becomes more tender. The myofibrillar proteins harden as they are heated and become tougher. The optimum combination of collagen dissolving and myofibrillar hardening happens at about the temperature of medium-rare. Yum.

    Some people don’t like the serumy (bloody) flavor associated with medium-rare and they want their steaks cooked longer (my mom). I guess that’s ok. If you like more well done steaks, I suggest you buy steaks with more marbling (USDA Choice, Prime, and Certified Angus Beef). The extra marbling protects the tenderness of those steaks when you cook them more.

    Like I said, there is really no wrong answer to the question, “how would you like your steak cooked?”

    However, you must cook hamburgers to medium (160°F) or greater.


    1. I'd have to side with your mom on how I like my steaks cooked! ...But even though my husband may know a lot of this from the restaurant business, it was very informative for me! Thanks for sharing!

    2. Your blog is so informative! I love the way you break down our beef! I know you focus mainly on beef but does this same situation apply to pork? We butcher our own beef and pork and also make hamburger and sausage from our own grinder. Is there any way to cut down on bacteria or is the only option to completely cook the meat?

      Where the Blacktop Begins

      1. Thanks for the great comment!

        Yes this information applies to pork as well as beef, but ALL chicken should be cooked to 165 F.

        There are ways to decrease the bacterial load on the surface of the trim before it is ground, like organic acid sprays and several others. However, none of those methods will completely eliminate the bacteria, so I always cook ground products (beef and pork) to 160 F. Even cooked to 160, your hamburgers and pork burgers should still be nice and juicy.

        Thanks again,

    3. This is seriously fascinating! Thank you for the great info!!! (That sounds like a spam content, but I mean it!)


      1. Thanks for the info! But what about parasites? Do they die at a lower temperature?

    4. Thanks for the info! But what about parasites? Do they die at a lower temperature?

      1. Gloria, Please forgive me for the lateness of my reply.

        Yes, parasites die at lower temperatures. And in the US, when you are cooking non-game meat, like what you'd buy at the store, parasites should not be a problem. Our pork in the US has been parasite free for several years.

        If you are cooking wild game like bear or wild boar, I would be a little more concerned about parasites. I would be sure to cook it to 160, just to be safe.

        Great question,