EU Science Hub

Semi-Quantification in GMO analysis: a step forward to improve laboratory capacity

Oct 27 2016

JRC scientists developed a semi-quantitative approach that allows predicting GMO content when food and feed samples are analysed with pre-spotted plates. The statistical model was verified on data from spiked and proficiency test samples and is expected to reduce standard quantitative tests by 70%.

European Union policy on GMO foresees the traceability of GM-derived food and feed, from the farm to the fork in order to guarantee freedom of choice to EU citizens. Given the challenges to avoid unintentional contamination by GMO within the production chain, EU legislation established a 0.9% tolerance threshold for labelling, provided that the contamination is unintended and technically unavoidable. Nevertheless, every GMO must be previously authorised before being placed on the EU market in order to guarantee the safety of human, animal health and the environment.

Over the years, the increasing number of GMO placed on the EU (and global) market made the control more and more demanding. GMO analysis normally requires a complex multi-step procedure: in the first step, screening tests reveal whether the sample contains any GM material; then, more specific tests are used to identify which GMO is present and to assess its authorisation status; finally, quantitative assays, which are more expensive in terms of time and costs, are needed to verify the fulfilment of labelling provisions.  Quite often, samples are submitted to the quantitative assessment, but the analysis then reveals that only traces of the GM event are present, thus indicating that the content is below the legal threshold or even not quantifiable. In these cases, the quantification represents a laboriously unnecessary and costly step.

Exploiting a previously developed ready-to-use PCR system for GMO detection, known as pre-spotted plates, JRC scientists have recently developed a novel semi-quantitative approach that is expected to reduce standard quantitative tests by 70%. Pre-spotted plates are a multi-target analytical system for the detection of several GM events in a single PCR experiment. The combined use of the pre-spotted plates and a statistical model for semi-quantification allows performing, in one single step, both the GMO identification and the categorization of samples based on their GMO content. Although semi-quantification does not provide the exact GMO content, it gives an indication of the amount of a certain analyte (in the specific case, establishing whether above or below the defined 0.9% threshold), therefore, greatly reducing the number of samples that need further quantitative analysis. This innovative approach was successfully challenged on spiked and proficiency test samples and, once implemented, is expected to help laboratories in significantly reducing time and resources for GMO analysis.

©EU, 2016

Read more in: Gatto F. et al. "Semi-Quantification of GM Maize Using Ready-To-Use RTi-PCR Plates" in Food Analytical Methods (2016) doi:10.1007/s12161-016-0609-0