Study On Liquid Milk Polluted By Enterobacter Sakazakii

Food safety emergencies are high frequency in recent years in worldwide.More and more people pay attention to food safty.Enterobacter sakazakii is considered an opportunistic pathogen and has been implicated in food diseases causing meningitis, bacteremia or necrotizing enterocolitis.Specially in neonates and infants.The fatality rates have reached above 20%-50%.In this study,the use of chromogenic media to detect Enterobacter sakazakii form liguid milk quickly and the time of detection was shortened by 1^2d.The cost was cut down.The result indicates:the sensitivity of the method is 100%.In this study,Comparative study on biologic characteristics of Enterobacter sakazakii isolated from liquid milk and standard bcteria.Kunming female mice selected, clean grade,weighing 18-22g,divided into 6 groups each group has 10 mice to do comparative reserch on the toxicity of Enterobacter sakazakii isolated from liquid milk and standard bcteria,we took use of E.sakazakii of special sequences of conservative 16SrRNA to design a special primers.The reaction mixture consisted of 50μL:6μL 10×PCR buffer, 4μL mixture of dNTPs,2.5μL Mg2+(25mM),μL of 10μmol forward primer,2μL of 10μmol reverse primer,0.25μL(5U/μL) Taq enzyme,ddlH₂O 23.25μL.DNA pre-denaturation at 95℃for 5 min,DNA denaturation at 95℃for 1min,primer annealing at 61℃,run 35 cycles.The PCR products were examined by 2%agarose gel electrophoresis.we use improved method to detecting Enterobacter sakazakii in a batch of 167 samples of liqiud milk.There are four strains were detected.The detection rate was 2.39% and the detection rate using the standard cultivation method was 1.79%.There were three strains detected from 120 pasteurized milk samples,and the detected rate was 2.5%.There was one strain islated from 47 sterilized milk samples,and the detection rate was 2.1%.