| Popis: |
Traditional microbiological techniques for the isolation and identification of bacteria from foods have depended on obtaining pure cultures. Enrichment and selection steps are often time-consuming and the biochemical identification of a particular species may add several days to the procedure. Such methods are insufficient when an outbreak of foodborne disease is occurring or food products with short shelf-lives must be tested. DNA hybridisation methods first developed for research use in the molecular biology laboratory, such as DNA gene probes used for colony hybridisation (Grunstein and Hogness, 1975), and the polymerase chain reaction (PCR, Saiki et al., 1985) have shortened the time required for analysis, by obviating the need for pure cultures. Very rapid PCR methods have been developed that allow the analysis of some food samples within? 3–4 h. The basic mechanism of the PCR and its variations will be discussed. Examples of how PCR has been applied to the detection of particular foodborne pathogens will be presented. |
