OGM: soglie di tolleranza per le sementi e metodiche analitiche – 2° parte.

GMOs: thresholds for seeds and analytical methods – Critical aspects of detection and quantification Despite the high sensitivity and precision of the currently available PCR systems, the low levels of contaminants that must be determined represent a challenge for the methods aimed at the detection and quantification of GMOs. Sampling error can occur not only in the warehouse, but also in several subsequent processing steps in the laboratory. This source of variability has to do with the uneven distribution of the GM particles (seeds, flour granules, DNA molecules) in the sample and with its relatively small size, and increases as the concentration of the target decreases. Secondly, the accuracy of the analytical methods strongly depends on factors affecting the effi- ciency of the reaction, the nature of reference material and the genetic constitution of the contaminant seeds. All these aspects should be carefully taken into account in the definition of workable thresholds for the degree of reliability of the currently available analytical tools.