Evaluation of multiplex PCR assay sensitivity for universal, cow, donkey and pork in cooked labortaty prepared samples; M: Marker 100-bp. NC: Negative control (reagents with primers without DNAs); Eu: Eukaryotic DNA positive control. (1) 24%, (2) 12%, (3) 6%, (4) 3%, (5) 1.5%, (6) 0.75%, (7) 0.05% (8) 0.005% (9) 0%.