Stephen W. Paddock - Digital Image Gallery
Cells on a Glass Fiber
Living tissue culture cells are captured growing on a glass fiber with the aid of reflected light microscopy. This unusual image reveals a single cell in the center of the image that appears to display fibroblast morphology.
As the meat cooks, there is a physical unfolding and denaturation of the proteins in animal muscle tissue as a direct response to thermal agitation. Unstained meat goes from deep red to pale gray or brown as it cooks and the myoglobin degrades to the point at which it can no longer bind oxygen (82 degrees Celsius). As heat is applied to the raw meat, muscle fibers shorten and toughen, until the muscle structure eventually breaks down in fully cooked meat. When meat is overcooked, the connective tissue (primarily composed of collagen) undergoes complete denaturation into a gelatin-like mass. Overall, cooked meat becomes less structured and easier to chew. Because of worries with bacterial contamination and harmful parasites in undercooked meats, color is not sufficient to judge degree of cooking, and therefore, a meat thermometer or an image captured by the light microscope may be far more reliable (although sometimes not practical). Staining for some types of bacteria will also highlight potential health problems.
