It was with interest that I read recent press articles about calls to label modified foods. I was most interested in the comments on the perceived link between the threshold for labelling and the cost of labelling.

First , whether the threshold is 5% or 1%, there is no cost difference in laboratory testing - I should know as I run the GMO Testing Facility that performs routine genetic modification detection in SA.

Further, the regulations make provision for companies to assume an ingredient contains genetically modified matter if it was derived from a crop for which there is a genetically modified equivalent being produced in SA, such as maize or soybean. In such a case, no laboratory testing would be required, with no additional cost to the company. Compared to this, companies that want to indicate an ingredient has not been genetically modified would be required to verify this using laboratory tests - but this is no different to what is being practised.

Second , the proposition that genetic modification labelling will increase food costs 10% to 20% is unfounded and based on misinformation. In a comprehensive study in the European Union (EU) it was estimated that the added cost to food of genetic modification labelling ranged from 0,01% to 0,17%, depending on the stringency required. The EU system for genetic modification labelling is considerably more stringent than in SA and from this it is reasonable to suggest that the labelling cost to food would be much lower in SA.

There has never been a documented report that genetic modification labelling has led to a cost increase in food anywhere. What is being implemented in SA can be considered a minimum level compared to genetic modification labelling in other countries, including Australia, Brazil, China, New Zealand and the EU.

Third , the comment that some food products "cannot be accurately analysed or labelled because they do not contain detectable protein" is misleading. It is true that processing destroys protein, making it undetectable, but the world standard for performing genetic modification analysis on food is not based on detecting protein but rather DNA (the molecule responsible for making the protein).

DNA is considerably more stable than protein and genetic modification detection laboratories around the world routinely analyse highly processed food ingredients, including starches and oils.

It is true, however, that extremely processed products cannot be tested accurately for genetically modified content as even the DNA may be destroyed. In such cases the ingredients used to make the extremely processed product can be tested .

Finally, genetic modification labelling is no different to labelling foods for the presence of additives or colorants - common practice in SA. There is no report that this practice has resulted in any food cost increase either. If consumer rights are truly autonomous, genetic modification labelling should be no exception.

Prof Chris Viljoen

GMO Testing Laboratory, University of the Free State