How to Avoid Turkey Trouble.

      The last few leaves are falling from the trees, the nights are getting colder, and families are making plans to reunite over a table spread with all sorts of delicious, traditional foods - that's right, Thanksgiving is coming!  It's one of my favorite holidays of the year and, since I enjoy cooking, I am always interested in making the food, from the turkey and stuffing to the cranberry relish.  In fact, my interest in making the food is only surpassed by my interest in eating it.  Recently, my education in the medical field has started playing a larger role in my life, so the potential risk of salmonella is a topic that I can relate to and understand, but fortunately it can easily be avoided.

Salmonella is shown here in pink.

      Salmonella is a gram-negative bacteria that can be found in uncooked or under-cooked food.  When it enters the human digestive tract, it can cause the traditional symptoms of food poisoning, such as nausea, fever, and dehydration, among others.  It is rarely a dangerous disease, and only causes around 30 deaths a year in the United States.  It functions by attacking the innate immune system, or the line of defense in the body that is not specific to any pathogen but involves immune system cells that attack any pathogen the body detects.  Testing for salmonella isn't a very difficult task as many strains are readily identifiable on specific cultures or in specific media.  These identification techniques include agar plates containing ferrous sulfate which take advantage of the bacteria's production of hydrogen sulfide, or the use of a Triple Sugar Iron slant.
      Preventing a salmonella infection is a relatively simple task.  Thoroughly washing the food in question will help to minimize the amount of bacteria present, as will taking steps to prevent cross-contamination between cooked and raw foods, and thawing foods in the refrigerator or in cold water before cooking.  If the salmonella is present on food such as uncooked poultry or eggs, thoroughly cooking it will kill the bacteria.  The recommended internal cooking temperature for turkey is 165°F, and to minimize the risk of infection further, it is advised to cook dressing separately instead of inside the bird (when it becomes stuffing according to the rules of food nomenclature).  Also, leftovers should be refrigerated within 2 hours to prevent to growth of bacteria.  Following these simple steps will help reduce the risk of infection with salmonella and ensure your Thanksgiving dinner goes off without a hitch.  Happy feasting!!

       Information in this article was found here and here.
  
Added 11-17-2011:  In response to some helpful comments, here is some more information about the tests for salmonella , in particular the Triple Sugar Iron (TSI) slant.
      The TSI slant tests for multiple types of reactions that some bacteria can perform on 3 sugars (glucose, lactose, and sucrose) and on ferrous sulfate.  The medium contains these compounds as well as phenol red, a pH indicator, which measures the degree to which the bacteria has fermented any of the sugars; the formation of cracks or gas bubbles is also used to determine if fermentation occurred.  In addition, if the bacteria is capable of reducing the sulfate in the media, it produces hydrogen sulfide, which then reacts with the iron present.  The results from these reactions are all visible in the same tube and therefore allow multiple properties of the bacteria to be tested for, meaning more precise diagnoses can be made off of 1 tube as compared to media that only tests 1 aspect of the pathogen.

TSI slants of various bacteria.

       Interpreting the slants is based off of the location of colored regions in the medium.  There are 2 regions used for identification: the slant, or the top half of the media, and the butt, or the bottom half.  A color change in the slant from red to yellow (indicating acidic conditions) means that the bacteria can ferment sucrose or lactose, while a similar color change in the butt means that it can ferment glucose, at least to some extent.  A lack of color change is indicative of an obligate aerobe, or a bacteria that requires oxygen to grow.  If there are cracks or bubbles in the agar, that is additional evidence that fermentation has taken place as carbon dioxide gas is a by-product of this reaction.  If there is a black region at the bottom of the slant, the bacteria produced hydrogen sulfide, which then formed ferrous sulfide, a black compound.  Salmonella (which is present in the third tube from the top in the picture at right) results in a red slant, yellow butt, and a black region, with some strains also producing noticeable gas from fermentation.  The yellow butt of the tube is obscured by the extensive reduction of ferrous sulfate to ferrous sulfide.
      The agar plates used to test for salmonella are similar to the TSI slants, except that they only test for the production of ferrous sulfide.  These tests are not as definitive as the TSI slants since they do not test for other properties of the bacteria in question.
      The information and picture for this section was obtained here.