Establishment Of The Detection System For Pathogenic Bacteria In Meat And Dairy Products And Studies On The Identifying Genotyping And Tracing Of Listeria

Many kinds of pathogenic bacteria in meat and dairy products are the fatal factors to the food safety and physical health of human beings. Currently, the domestic and foreign inspection methods of detecting the pathogenic bacteria are mostly on the level of low efficiency and single target. This research has established the detection system of the pathogenic bacteria in meat and dairy products, species identifying, serotyping and epidemic strain detection using Polymerase Chain Reaction (PCR) combining with denaturing high performance liquid chromatography (DHPLC). Meanwhile the research has studied the identifying, genotyping and tracing of Listeria using matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF-MS). The results of the research are as follows:1. The individual detection methods for 10 common pathogenic bacteria in the meat products, including Salmonella, Staphylococcus aureus, Listeria monocytogenes, Campylobacter jejuni, Yersinia enterocolitica, Streptococcus hemolyticus, Enterotoxigenic E. coli, Enterohemorrhagic E.coli O157:H7, Enteropathogenic E.coli, Enteroinvasive E.coli were established using PCR-DHPLC. On the base of above, the simultaneous detection systems for six pathogenic bacteria, including Salmonella, Staphylococcus aureus, Listeria monocytogenes, Campylobacter jejuni, Yersinia enterocolitica, Streptococcus hemolyticus were established and the simultaneous detection systems for four pathogenic bacteria, including Enterotoxigenic E. coli, Enterohemorrhagic E.coli O157:H7, Enteropathogenic E.coli, Enteroinvasive E.coli were also established. All the above systems were developed for the first time worldwide.2. The individual detection methods for 8 common pathogenic bacteria in the dairy products, including Enterobacter.sakazakii, serratia macescens, Pseudomonas aeruginosa, Proteus vulgaris, Proteus mirabilis, Klebsiella peneumoniae, serratia odorifera, Aeromonas hydrophila were established using PCR-DHPLC. On the base of above, the simultaneous detection systems for four pathogenic bacteria, including Enterobacter.sakazakii, serratia macescens, Pseudomonas aeruginosa, Proteus vulgaris were established and the simultaneous detection systems for four pathogenic bacteria, including Proteus mirabilis, Klebsiella peneumoniae, serratia odorifera, Aeromonas hydrophila were also established. All the above systems were developed for the first time worldwide.3. The rapid detection method for the family of Listeria was established for the first time worldwide.using PCR-DHPLC by designing and screening out specific primers.4. The high throughput detection methods for 3 pathogenic bacteria of Listeria family, including Listeria monocytogenes, Listeria ivanovii, Listeria innocua were established using multiple PCR-DHPLC for the first time worldwide.5. The high throughput detection methods for 2 main serotype (1/2a and 4b) with high clinical infection rate of Listeria monocytogenes were established using multiple PCR-DHPLC for the first time worldwide.6. The high throughput detection methods for 3 main epidemic strains (ECⅠ、ECⅡ、ECⅢ) of Listeria monocytogenes were established using multiple PCR-DHPLC on the base of the identification function of DHPLC at non-denaturing condition for the first time worldwide.7. The high throughput detection methods for 6 species of Listeria, including Listeria monocytogenes, Listeria ivanovii, Listeria innocua, Listeria welshimeri, Listeria seeligeri, Listeria grayi were established using multiple PCR-DHPLC on the base of the identification function of DHPLC at non-denaturing condition for the first time worldwide.8. The identifying database for Listeria monocytogenes was established using MALDI-TOF-MS on the base of the standard MALDI-TOF-MS result charts of 37 isolated strains of Listeria monocytogenes. On the base of above, cluster subtyping and tracing research was done at the 37 isolated strains of Listeria monocytogenes.Above all, this research has firstly developed the rapid, accurate and high throughput detection systems for common kinds of pathogenic bacterium of meat and dairy products. Also, the MALDI-TOF-MS identifying database for Listeria monocytogenes was established and cluster subtyping and tracing research was done systematically. The results of the above research have a signicant meaning to the rapid detection and initiative monitoring of food borne pathogenic bacteria as well as the prevention and tracing back of the serious food origin disease.