DNA degradation in chilled fresh chicken studied with the neutral comet assay

DNA degradation in fresh chicken was studied with the neutral comet assay, Chicken legs were stored in a refrigerator at: 2-4 degrees C. DNA from muscle tissue was analysed independently by the authors in Mol and Uppsala after 1-12 days. The cells were imbedded in agarose on a microscope slide, lysed and subjected to electrophoresis causing DNA and its fragments to migrate in the gel. The patterns ("comets") formed by the migration indicated the status of DNA. The comets were evaluated both with a fluorescence microscope by visual inspection (H.C.) and computer-assisted image analysis (G.K.). On day 11 a majority of the cells showed comets with very short tails, or no tail at all. A few cells showed advanced stages of DNA degradation. The number of these cells increased with time, as well as the degree of degradation. The bacterial contamination, which was rare on day I, increased with lime, and gave a characteristic background to day 10 samples. It was concluded that the neutral comet assay could be used as a method to rapidly screen fresh chicken in order to assess its quality.