Detection of genetically modified maize in processed products, dry grains, and corn ears intended for fresh consumption in South Brazil

Abstract

ABSTRACT. Conventional and genetically modified (GM) maize cultivars have been widely planted in Brazil to produce grains for processed food, feed, or to be consumed fresh as corn ears. This study used real-time PCR to detect GM maize in processed products and fresh commercial corn ears produced in the last two years in South Brazil. Eighteen conventional and GM maize cultivars were obtained from seed production companies and 50 commercial samples (including canned corn, corn flour, dry grains, and fresh corn ears) were purchased in small local stores and supermarkets. All samples were analyzed by real time TaqMan PCR to detect one constitutive maize gene (hmg) and three genetic regions present in GM plants (p-35S promoter, major gene cry 1A.105, and t-Nos terminator). Each commercial sample was classified as conventional or GM based on the PCR results. PCR targeting the 2 C.A.M. Oliveira et al. Genetics and Molecular Research 15 (4): gmr15048818hmg gene generated positive results from all DNA samples, which were further tested with the GM targets. These targets were not detected in the five conventional maize cultivars, but were detected in the GM seeds hosting these fragments. Analysis of processed foods identified four cultivars as conventional and six as GM, which were mostly correctly labeled. Seven (53.8%) dry grain samples were classified as conventional, while six (46.2%) were classified as GM. Three (11.1%) corn ear samples were identified as conventional, and the remaining 24 (88.9%) were GM maize. These results demonstrate the high frequency of GM maize in processed products, including fresh corn ears intended for consumption in South Brazil.

Contamination of corn grain for human consumption with transgenic sequences in Paraguay

“…The results showed that only five of the corn flour samples had the correct specifications on their label indicating that it is a product based on transgenic corn. On the other hand, almost 90% of the ears were positive for at least one GM target, demonstrating the great use of genetically modified cultives to produce commercial ears for human consumption (Oliveira et al, 2016).…”

Influence of Heat Processing on DNA Degradation and PCR-Based Detection of Wild-Type and Transgenic Maize

“…At present, various PCR-based methods have been developed for maize identification and for the detection of GM varieties [5,[19][20][21][22][23][24][25][26][27][28]. e conventional PCR methods targeted at the invertase gene [23,24], Zea mays 10 KDa zein gene [25], and quantitative real-time PCR assays targeted at zein, and alcohol dehydrogenase I (Adh-1) genes [26] and starch synthase IIb gene [27] were developed and successfully used for specific identification of corn.…”