ABSTRACT
Because of speed, specificity, and sensitivity, molecular methods are increasingly being developed to detect, identify, and quantify micro-organisms in food. The introduction of one of these methods, the polymerase chain reaction (PCR) (Mullis et al. 1986) has revolutionized molecular diagnostics with its speed (down to five hours or less), specificity, selectivity, and sensitivity (single nucleic acid target; for review see Lübeck and Hoorfar 2003). Further development of the method in the 1990s has led to real-time PCR, which combines the DNA amplification of conventional PCR with nucleic acid detection by fluorescent substances during amplification, rather than after the completion of amplification (Higuchi, Dollinger, Walsh, and Griffith 1992; Higuchi, Fockler, Dollinger, and Watson 1993). This further reduces the analysis time and sample handling during the process and also offers the opportunity to acquire quantitative data (Orlando, Pinzani, and Pazzagli 1998). Nonetheless, there are still limitations to the use of PCR for food-borne quantification that need to be overcome (Klein 2002).
