Use PCR to detect pathogens.The diversity of foodborne pathogens continues to increase. This is partly due to environmental stress factors, including food preservation food preservation, methods of preparing food so that it can be stored for future use. Because most foods remain edible for only a brief period of time, people since the earliest ages have experimented with methods for successful food preservation. processes. These techniques may lead to changes in pathogen genotypes and in the resistance or virulence of bacteria. This makes detection and identification of pathogens a complex task that requires better techniques. As you may know, the polymerase chain resection (PCR PCR polymerase chain reaction. PCR abbr. polymerase chain reaction Polymerase chain reaction (PCR) ) is a sensitive molecular genetics molecular genetics n. The branch of genetics that deals with hereditary transmission and variation on the molecular level. technique in which the DNA DNA: see nucleic acid. DNA or deoxyribonucleic acid One of two types of nucleic acid (the other is RNA); a complex organic compound found in all living cells and many viruses. It is the chemical substance of genes. of a single cell, treated with polymerase enzymes, is induced to replicate many times. This enables the DNA to be amplified in sufficient quantities to permit genetic analysis. PCR methods are extremely sensitive and specific to bacteria. They are based on the multiplication of the isolated pathogen DNA and the identification by electrophoresis of the DNA in the microbes. Even though PCR-based analytical kits are already on the market, standardization and validation of routine PCR analyses are needed. Scientists in Europe are attempting to validate a simple method for purifying DNA from bacterial cultures. They also want to establish a central collection of certified DNA sample materials and a databank containing key food pathogen DNA sequences. The researchers would like to develop standardized reagents and will attempt to validate certain pre-PCR sample treatment methods. This project involves a consortium of 35 institutes, companies and universities across Europe. Researchers will devise standardized PCR-based detection methods for five major pathogens: S. enterica, thermophilic ther·mo·phil·ic adj. Requiring high temperatures for normal development, as certain bacteria. Campylobacter Campylobacter Genus of gram-negative spiral-shaped bacteria infecting mammals. Many species, especially C. fetus, cause miscarriage in sheep and cattle. C. jejuni is a common cause of food poisoning. Sources include meats (particularly chicken) and unpasteurized milk. spp., enterohemorrhagic E. coli E. coli: see Escherichia coli. E. coli in full Escherichia coli Species of bacterium that inhabits the stomach and intestines. E. coli can be transmitted by water, milk, food, or flies and other insects. , L. monocytogenes and Y. enterocolitica. The effort entails producing certified DNA material, preparing a thermocycler validation guideline and performing PCR trials. Another important focus will involve the development of automated detection methods. The most important outcome to date has been the development of a guideline and a biochemical kit for validating different types of thermocyclers. Also, a simple method for purifying DNA from bacterial cultures has been developed. Reference DNA material has been produced that eventually will be made available. An online PCR database is under construction. The databank will list strains for specificity testing. Further information. Jeffrey Hoorfar, Danish Veterinary Institute, Bulowsvej 27, DK-1790 Copenhagen, Denmark; phone: +45 35 30025; fax: +45 35 300360; URL URL in full Uniform Resource Locator Address of a resource on the Internet. The resource can be any type of file stored on a server, such as a Web page, a text file, a graphics file, or an application program. : http://www.dfvf.dk/. |
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