Testing for foods derived from modern biotechnology: opportunities and limitations for metrology

Various countries have established labeling schemes for food derived from modern biotechnology. As a consequence, test methods need to be available to industry and regulators. The three test options, bioassays, protein-based and DNA-based test methods, are discussed. None of these methods is able to directly measure the percentage of foods derived from modern biotechnology by weight (weight-%), the unit in which most of the thresholds for food labeling in the different countries (if any) have been established. The conversion of the measurement units to weight-% is difficult to achieve and influenced by a number of biological factors. Metrology can aid the standardization of methods enormously by defining clearly the relationships between measurement units and other units of interest (e.g. legal thresholds).