IMMOBILIZATION WITH METAL HYDROXIDES AS A MEAN TO CONCENTRATE FOOD PATHOGENS FOR INCREASING SENSITIVITY OF PCR BASED DETECTION METHOD

Abstract

Polymerase chain reaction (PCR) based bacterial detection without enrichment step could be applicable by concentrating bacteria from food matrix by metal hydroxide. The false positive from exogenous DNA of dead cells could be eliminated by DNase I treatment,  one step before DNA extraction. DNase I facilitated for DNA removal DNA from dead- cells and had no detectable damaging effect signal on the DNA presented in livelintact cells. Double-stranded DNA dye SYBR green I was used in the real time PCR to quantify the amplicon production. In immobilization process, bacterial recoveries ranged from 93.6 to 99.3% for both metal hydroxides compared to 31.5.54.70% with no immobilization. When seeqed in 10 ml of whole milk, sample volume was reduced 50 - fold after immobilization by zirconium hydroxide.