Using the power of digital image processing, Dr. Paddock has transformed a remarkable confocal microscopy image of muscle tissue into a work of art. The concentric rings in the image represent striated fibers in the tissue.

Muscle Tissue Specimen: Muscle Tissue Technique: Fluorescence (Digital Image Processed)

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.