Abstract: This paper reports the application of PCR, Biotinylated probe labeled by PCR and culture methods for detection of L. monocytogenes in 68 pork samples and 70 milk samples collected from some free markets in Changchun city. The sensitivity of the above three tests have been compared. There are 41 positive samples in PCR test; 33 positive samples in dot-blot test and 22 positive samples in culture method. The ratio of the positive rate of the above three tests was as following: 100. 00 : 73. 32 : 48. 88. PCR reacted positively to all strains of L. monocytogenes , but negatively to other species of Listeria and bacteria. It is concluded that PCR is the most sensitive , simple and rapid method for detection of L. Monocytogenes in food , but for large quantity of samples , dot-blot test with the probe may be helpful.

Key words:  , PCR Probe Culture Pork Milk L. Monocytogenes；