Foodborne pathogens in retail oysters in south China.
OBJECTIVE
To investigate the occurrence of important foodborne pathogens in shellstock Pacific oysters in the food markets in South China.


METHODS
From July 2007 to June 2008, retail oysters were collected in different seasons from South China and analyzed for the prevalence and levels of Listeria monocytogenes, Vibrio vulnificus and Vibrio parahaemolyticus.


RESULTS
None of L. monocytogenes could be detected in any of the 202 oyster samples tested, while E vulnificus and V. parahaemolyticus could be detected in 67 (54.9%) and 109 (89.3%) of the 122 oyster samples analyzed, respectively, with an MPN (most probable number) value greater than or equal to 3. V. vulnificus and V. parahaemolyticus with a more than 102 MPN/g were found in 36 (29.5%) and 59 (48.4%) of the 122 oyster samples, respectively. The tdh and trh genes were detected in 4 (0.3%) and 8 (0.6%) of the 1 349 V parahaemolyticus isolates, respectively. Of the 122 samples, 4 (3.3%) was positive for either tdh or trh. The levels of V. vulnificus and total V. parahaemolyticus in oysters in South China varied in different seasons.


CONCLUSIONS
V. vulnificus and pathogenic V. parahaemolyticus are frequently found in oysters in south China, which may pose a potential threat to public health. Data presented here will be useful for the microbiological risk assessment in oysters in China.
Chen
Yan
Y
National Institute for Nutrition and Food Safety, Chinese Center for Disease Control and Prevention, Beijing 100021, China. yan_chen2000@yahoo.com.cn
Liu
Xiu-Mei
XM
Yan
Ji-Wen
JW
Li
Xiu-Gui
XG
Mei
Ling-Ling
LL
Mao
Qun-Fei
QF
Ma
Yi
Y
D000818:Animals; D002681:China; D003132:Commerce; D005516:Food Microbiology; D008089:Listeria monocytogenes / Q000302:isolation & purification*; D010125:Ostreidae / Q000382:microbiology*; D014736:Vibrio parahaemolyticus / Q000302:isolation & purification*; D041261:Vibrio vulnificus / Q000302:isolation & purification*