Presence of glyphosate in food products in South Africa of which maize or soybean is the primary constituent - Koortzen, B. J. (University of the Free State, 2017)
South Africa is considered a major GM crop producing country. The predominant GM trait in maize and soybean in South Africa is herbicide tolerance. Herbicide tolerant (HT) crops allow for the application of herbicide during the growing season to selectively kill weeds without damaging the crop. Glyphosate is the most widely used herbicide on HT crops in South Africa and the world. Glyphosate is absorbed by HT crops after application. Studies have detected levels of up to 2.2 mg/kg in HT maize and 26 mg/kg in HT soybean. Glyphosate is not removed from grain by washing, cooking or processing. As a result of this, glyphosate can also be detected in processed food products. It has also been found that glyphosate can be detected in animal tissue and urine after exposure to the herbicide through feed. Similarly, glyphosate has also been detected in the urine of humans, either as a result of occupational exposure, through diet and/or water. Pure glyphosate is considered safe by regulatory authorities and international bodies. However, recent studies have found that glyphosate in formulation at low concentrations results in endocrine disruption as well as DNA and chromosomal damage. As a result of this, the IARC re-classified glyphosate as a “probable human carcinogen”. Glyphosate is used on HT maize, a major staple food, and HT soybean, an important source of protein, in South Africa. Thus, the aim of this study was to determine whether glyphosate is present in commercially available South African food products containing maize and/or soybean as a primary constituent. The majority of food products tested in this study contained glyphosate. The level of glyphosate ranged from 0.027 mg/kg to 2.257 mg/kg that is below the MRL and ADI established in South Africa. However, recent studies have shown that glyphosate in formulation is genotoxic at the levels found in maize and soybean containing foods in South Africa. The results from this study found that the level of glyphosate in food products in South Africa is comparable to the limited number of studies from the UK and USA. This study is unique to other published studies since it focused on food products likely to be consumed daily. This study has confirmed that South Africans are exposed daily to low levels of glyphosate through food products. The GM HT events in the food products were quantified in order to explain the variation in the levels of glyphosate. It was determined that 57 products contained one or more GM HT event in a range of 0.25% to 100%. However, there was no correlation between the level of glyphosate and percentage GM HT event in the products, even when GM HT negative samples were excluded from the analysis. This suggests that either glyphosate is not applied to some GM HT crops, when weed control is not required, or that the herbicide is applied to non-GM crops as a desiccant prior to harvesting. Most of the food products used in this study were labelled in terms of GM content. The percentage GM HT event(s) in the food products was used to determine compliance to mandatory GM labelling in South Africa since the data was available. Results indicated that the majority of companies in South Africa are compliant with the Consumer Protection Act (2008) concerning GM labelling. However, most of the products labelled “GMO free”, did not comply with the expectation of discerning consumers. To conclude, this is the first study to investigate the extent of glyphosate in South African food products. This study has confirmed that South African consumers are exposed to low levels of glyphosate as a result of consuming maize and soybean food products. The level of glyphosate detected in the food products although considered low, is at a concentration reported to cause genotoxic effects at cellular level by in vitro studies. It is currently not known what the safety implications are of chronic exposure to glyphosate, through the consumption of a staple like maize meal and soybean in South Africa. The question of whether glyphosate in food is safe in the long term needs to be addressed through future research.

Suid-Afrika is werêldwyd bekend as die negende grootste produsent van GM gewasse en verbou hoofsaaklik GM mielies, sojabone en katoen. Onkruiddoder toleransie is die grootste GM eienskap in Suid-Afrika en kom voor in ongeveer 75% van alle GM gewasse wat geplant word. Onkruiddoder tolerante (OT) gewasse laat die direkte toediening van onkruiddoder toe, sonder om skade aan die gewas aan te rig. Die gewildste onkruiddoder in Suid-Afrika asook werêldwyd is glifosaat en word hoofsaaklik gebruik vir toediening op OT gewasse. Verskeie studies het getoon dat glifosaat geabsorbeer word deur OT gewasse na toediening. Glifosaat vlakke van tot 2.2 mg/kg is waargeneem in OT mielies en tot 26 mg/kg in OT sojabone. Glifosaat kan nie verwyder word van graan deur dit te was, gaar te maak of te prosesseer nie. Die resultaat hiervan is dat glifosaat gevind word in geprosesseerde voedsel produkte. Verskeie studies het aangedui dat glifosaat geabsorbeer word en voorkom in die weefsel, uriene en fesus van diere wat gevoer is met glifosaat behandelde grane. Glifosaat is ook gevind in menslike uriene, hoofsaaklik as gevolg van kontak met die onkruiddodder tydens landbou praktyk of deur die inname van glifosaat bevattende voedsel en water. Verskeie internasionale owerhede beskou suiwer glifosaat as veilig vir mense en diere. Onlangse studies het egter bevind dat glifosaat in formulasie toksies is teen lae konsentrasies. Die bevindinge sluit endokriene ontwrigting asook DNA en chromosomale skade in wat voorgekom het in beide mens en dierselle. In 2015 het die Internasionale Agentskap vir Navorsing oor Kanker (IARC) glifosaat geherklassifiseer as “waarskynlik karsinogenies vir mense”. OT mielies in die vorm van mieliemeel is ‘n stapelvoedsel in Suid-Afrika en OT sojabone is n belangrike bron van proteїene. Beide hierdie gewasse word ekstensief behandel met glifosaat gedurende die groeiseisoen. Die doel van hierdie studie was dus, om te bepaal of glifosaat voorkom in kommersieël beskikbare Suid-Afrikaanse voedsel produkte, wat mielies of sojabone as die primêre bestanddeel bevat. Glifosaat kom voor in die meerderheid van voedsel produkte getoets in hierdie studie met vlakke wat wissel van 0.027 mg/kg tot 2.257 mg/kg. Die vlakke van glifosaat in die voedsel produkte was onder die toegelate limiete (MRL en ADI) vasgetel vir hierdie onkruiddoder in Suid-Afrika. Onlangse studies dui egter aan dat glifosaat in formulasie toksies is teen konsentrasies gelykstaande aan wat voorkom in Suid-Afrikaanse mielie en sojaboon voedsel produkte. Die resultate van hierdie studie dui aan dat die konsentrasies glifosaat gevind in Suid-Afrikaanse voedsel produkte vergelykbaar is met die vlakke gevind in voedsel produkte van die Verenigde Koninkryk (VK) en die Verenigde State van Amerika (VSA). Hierdie studie is egter uniek omdat dit gefokus het op stapelvoedsel produkte wat daagliks geëet word. Die studie bevestig dat Suid-Afrikaners daagliks blootgestel word aan lae vlakke glifosaat deur hulle dieet. Reële-tyd PKR was gebruik om die persentasie OT geen te bepaal wat voorkom in elke produk. Hierdie resultate het aangedui dat 57 uit die 81 produkte ‘n OT geen bevat met vlakke wat wissel van 0.25% tot 100%. Geen korrelasie is egter gevind tussen die persentasie OT geen en die vlak van glifosaat in die produkte nie. ‘n Verdere ondersoek is gedoen na al die produkte wat negtief getoets het vir n OT geen verwyder is, maar steeds is geen korrelasie gevind nie. Die bevindinge stel voor dat glifosaat nie noodwendig toegedien word tot alle OT gewasse nie. Dit kan verduidelik hoekom sommige voedsel produkte positief was vir n GM OT geen, maar geen glifosaat bevat nie. Dit word beskou as algemene landbou praktyk on nie-OT gewasse te spuit met glifosaat, om hierdie gewasse egalig uit te droog voor dit geoes word. Die bogenoemde verduidelik hoekom sommige produkte glifosaat bevat maar vry is van ‘n GM OT geen. Die voedsel produkte was ook ondersoek in terme van GM etikettering aangesien die persentasie GM OT geen per produk reeds bepaal was en meeste produkte ‘n GM etiket bevat het. Die resultate van hierdie studie bevestig dat die meerderheid van maatskappye wat GM bevattende produkte produseer, voldoen aan die Wet op Verbruikersbeskerming ingestel ten opsigte van GM etikettering in Suid-Afrika. Die resultate dui egter aan dat sommige produkte gemerk “GMO vry”, wel GM OT gene bevat en dus kontrasteer met wat hul etiket aandui. As gevolg hiervan mag die “GMO vry” handelsmerk verwarring skep, spesifiek by individue wat nie-GM produkte verkies. Per opsomming, hiedie is die eerste studie wat ondersoek ingestel het ten opsigte van die voorkoms van glifosaat in die Suid-Afrikaanse voedselketting. Die studie het bewys dat Suid Afrikaners daagliks bloot gestel word aan lae konsentrasies glifosaat deur die inname van mielie en sojaboon voedsel produkte. Onlangse studies het egter bevind, dat glifosaat in formulasie by soortgelyke konsentrasies soos gevind in die voedsel produkte getoets in hierdie studie, toksies is vir beide mens en dier. Dit is tans onbekend wat die gesondheids implikasies mag wees van kroniese blootstelling tot ‘n lae konsentrasie glifosaat en moet dus in toekomstige studies ondersoek word.
Dissertation (M.Sc. (Haematology and Cell Biology))--University of the Free State, 2017
Keywords: Glyphosate; ELISA; GM crops; GM HT event detection; Food products; GM labelling; Herbicide tolerance; South Africa; Maize; Soybean