THE POLYMERASE CHAIN REACTION (PCR) TESTING OF LECITHIN WITH VERY LOW LEVEL OF PROTEIN AND DNA
The polymerase chain reaction (PCR) testing is used to identify lecithin derived from genetically modified organisms “GMO” or “non-GM” sources. The principle of PCR method consists in creation of DNA replications from a single sample of DNA which are subsequently examined for the presence of transgenic DNA.
Since lecithin is a processed product which contains very low level of protein, only a small number of DNA copies are present in a tested sample. Therefore PCR testing of lecithin delivers rather reliable results on the presence of GM material in tested samples, but quantifying the presence of GMOs in lecithin can be extremely unreliable and consequently it is challenging to determine whether a GM label is required or not*.
During a meeting of ELMA and the Joint Research Centre (Ispra, 2012), ELMA presented the unreliability of quantification of lecithin PCR testing in low DNA containing lecithins for samples with less than 80 copies 80** of DNA. The constraints associated with PCR testing of lecithin with a very low level of protein and DNA were acknowledged and further discussion with Joint Research Centre is on-going.
* Food and feed ingredients containing, consisting of, or produced from GMOs in proportion higher then 0,9% must carry a label which refers to the presence of GMOs (Regulation (EC) No 1830/2003).
** Waiblinger et al., J. Verbr. Lebensm. (2006), 1, 113-115