Detecting Main Food-born Pathogens By Using Thin-film Biosensor Chips

Global food security is a major strategic issue, not only related to the health of consumers, but also to the normal development of a country's economy and the government's prestige. At present, food-borne pathogens pollution is the primary food safety issue. There is an urgent need for research and development of all kinds of quick and easy detection of pathogens. Therefore a new pathogen detection technology was set up on the base of thin-film biosensor chip, and objective of the detection was specific gene sequences of common food-borne pathogens.According to Salmonella, Shigella, Staphylococcus aureus, Yersinia enterocolitica, Listeria monocytogenes, Campylobacter jejuni, Escherichia coli O157:H7, Vibrio parahaemolyticus, Vibrio cholerae, Enterobacter sakazakii, Pseudomonas aeruginosa, 23S rDNA gene sequences and pathogen-specific gene sequences were used respectively as the target sequences to design primers, and DNA of pathogens were amplified by the primers. All the PCR products which had been recovered and sequenced were contrasted with the design of primers and probe sequences to analysis effect of primer amplification. 11 kinds of specific probe and the positive control were pointed to a blank chip, and then the thin-film biosensor chips to detect pathogen were made. Those chips were hybridized with DNA templates which were PCR amplified with the specific primers. After antibody reactions of the hybridized chips and horseradish oxidase, there were blue dots on the yellow background. So whether probes and PCR products were combined especially were estimated and determine whether there were corresponding pathogens in the DNA templates.After the experiments and analysis on the PCR product, we found that rDNA gene was conservative relatively strong and could not be achieved identification requirements of the types of pathogens and identification of serotypes. There were large differences between specific gene sequences and the specificity was obvious, the results had high credibility in the identification of pathogens, and therefore this paper chose specific sequence of primer and probe as the target sequence. There were corresponding blue hybrid sites on the yellow background, and the results were clear, specific and the pollution of the background was low. The experimental operation was simple and reliable, less-time consuming, and had a good stability and repeatability. The detection sensitivity could be reached 8.5×101 cfu/mL, the sensitivity could be as low as 0.4cfu/g after overnight reaction.This study established a pathogen detection technology. The technology can detect two genus and nine kinds of common bacteria, and the technology is sensitive, efficient, accurate, simple, high-throughput, practical, and get rid of the dependence of fluorescence scanner. This study provides a new way and method for pathogens detection.