DNA was extracted using the Wizard Genomic DNA Extraction kit (Promega, Madison, WI, USA) under the following conditions. Small samples of whole tissue derived from beef, chicken, pork, and lamb were placed in microcentrifuge tubes. Each tube was then added with 600µl nuclei lysis solution, 120µl EDTA, and 17µl proteinase K. The microcentrifuge tubes were then incubated at 65°C for 75 minutes. The tubes were shaken every 15 minutes during the incubation stage. At the completion of the incubation period, the process to break down RNA began with adding 10µl RNase to each microcentrifuge tube. The tubes were then incubated at 37°C for 15 minutes. After incubation, the tubes were vortexed after 200µl protein precipitation solution was added to each. The tubes were then chilled in the freezer for 10 minutes, after which they were put into the centrifuge and ran at 13,300 g for 5 minutes. The DNA was then isolated in the –precipitating process of placing 600 µl room temperature isopropanol in 4 new microcentrifuge tubes. 600µl supernatant present after centrifuging was then extracted from each original microcentrifuge tube and then inserted into its respective new tube. The new tubes were then chilled for 10 minutes in the freezer. After chilling, the tubes were placed in the centrifuge and ran at 13,300g for 10 minutes. This resulted in the DNA pellet being isolated in each tube. Once removed from the centrifuge, the supernatant was discarded carefully. Then 600µl 70% ethanol was added to each tube to wash the pellet. The tubes were then placed back into the centrifuge, where they were ran at 13,300g for 5 minutes. After discarding the ethanol carefully, the pellet was air-dried at 37 °C for one hour and then dissolved with 100µl double-distilled water. DNA was extracted from the unknown ground meat samples using the same procedures described above.

For DNA isolated from whole meat samples, PCR amplifications were performed in a final volume of 20μl comprised of 4μl DNA template, 1.5μl forward species specific primer, 1.5μl reverse species specific primer (Table 1) (Lahiff, et al., 2001), 0.4μl 10mM dNTP, 0.5μl Taq enzyme, 4μl 5x Taq buffer, 2μl 25mM MgCl₂, and 6.1μl deionized water. PCR amplification was performed in a Veriti 96 well Thermal Cycler with the following conditions: denaturation at 95°C for 1 minute, annealing at 58°C for 1 minute, and elongation at 72°C for 1 minute.