Pilot survey of raw whole milk in China for Listeria monocytogenes using PCR

Milk of dairy cows can harbor a variety of microorganisms including Listeria monocytogenes, the first to be identified as an important foodborne pathogen. This pilot survey aimed to assess the presence of L. monocytogenes in raw whole milk in 15 provinces of China between June 2009 and October 2010. All 5211 analyzed samples were compliant using polymerase chain reaction (PCR) detection. A total of 19 samples were positive in 9 provinces, while no PCR-positive samples were obtained in the other 6 provinces. The prevalence of L. monocytogenes in raw milk was 0.36% in the 15 Chinese provinces, while the prevalence of positive areas within these dates was 0.23-1.2% among the nine provinces. Among the investigated 24 herds, rates of L. monocytogenes positivity were 0.17-2.89% in 13 herds, whereas they were 0% in the other 11 herds. There was a significant difference (p < 0.05) in PCR-positive data between organized farms (0.19%) and private herds (1.83%). These results indicate that there is a lower risk of contamination in the milking process in China when more attention is paid to maintaining good milking and strict hygiene practices, especially in private herds.