Cured Ham

My friends ate a cured ham with Thanksgiving dinner a few weeks ago.  They thought something like mold or fungus was growing on the outside.  I thought it was just salt, but I collected some into an eppendorf tube to look at later.  I went home for Thanksgiving and my friends stayed and cooked the ham.  They first washed the outside (removing what we though was salt or mold) and then soaked the entire leg in water for a day.  This was to draw out the salt that was used to cure the ham.  They then cooked it in the oven and enjoyed it.

About two weeks went by until I could look at the sample under the microscope.  By the time I put the sample on a microscope slide it had collected moisture and was much wetter than when I collected the sample.  

First, I scraped some of the sample on a number 1 coverslip, and mounted it on an inverted Nikon microscope with a 20x air objective (the 100um scale bar applies to all images).  At first I saw dried salt crystals.  As I looked at the sample it was drying out.  I switched from backlit to fluorescence, and some of the crystals were fluorescent!  They lit up the crystals around them.  The center and right images are in the same location, but the center image is fluorescent while the right is backlit.  Fluorescence was excited at a peak of 532 nm (blue-green) and the emission peak was at 595 nm (yellow-green).

Then I saw this large shadow, and it was moving!  It looked like a large bug.  I recorded a video over about 7 seconds, imaging frames as fast as possible.  Just after the video was recorded it stopped moving, and I could not get a better image of the bug.  I think it was alive and either dried out or got cooked to death by the lamp illuminating the stage.  

After some searching, I learned cured meats can harbor pests, including mites.  They are about 800um long  (which this one appears to be), and they have eight legs, four in the front and four in the back, with little hairs growing off the legs.  These live on the outside of the meat only and can be easily washed off.  This was a learning experience.  I don't think the mites were harmful, but they do look gross.