RESUMO
OBJECTIVES: In Ecuador, food products need to be labeled if exceeded 0.9% of transgenic content in whole products. For the detection of genetically modified organisms (GMOs), three DNA extraction methods were tested in 35 food products commercialized in Ecuador. Samples with positive amplification of endogenous genes were screened for the presence of the Cauliflower mosaic virus 35S-promoter (P35S) and the nopaline synthase-terminator (Tnos). TaqMan™ probes were used for determination of transgenic content of the GTS 40-3-2 and MON810 events through quantitative PCR (qPCR). RESULTS: Twenty-six processed food samples were positive for the P35S alone and eight samples for the Tnos and P35S. Absolute qPCR results indicated that eleven samples were positive for GTS 40-3-2 specific event and two for MON810 specific event. A total of nine samples for events GTS 40-3-2 and MON810 exceeded the umbral allowed of transgenic content in the whole food product with the specific events. Different food products may require different DNA extraction protocols for GMO detection through PCR. Among the three methods tested, the DNeasy mericon food kit DNA extraction method obtained higher proportion of amplified endogenous genes through PCR. Finally, event-specific GMOs were detected in food products in Ecuador.
Assuntos
Produtos Agrícolas/genética , DNA de Plantas/análise , Análise de Perigos e Pontos Críticos de Controle/métodos , Plantas Geneticamente Modificadas/genética , Caulimovirus/genética , Produtos Agrícolas/virologia , DNA de Plantas/isolamento & purificação , Equador , Contaminação de Alimentos/prevenção & controle , Rotulagem de Alimentos/métodos , Alimentos Geneticamente Modificados/virologia , Regiões Promotoras Genéticas/genética , Zea mays/genética , Zea mays/virologiaRESUMO
BACKGROUND: Papaya, a nutritious tropical fruit, is consumed both in its fresh form and as a processed product worldwide. Major quality indices which include firmness, acidity, pH, colour and size, are cultivar dependent. Transgenic papayas engineered for resistance to Papaya ringspot virus were evaluated over the ripening period to address physicochemical quality attributes and food safety concerns. RESULTS: With the exception of one transgenic line, no significant differences (P > 0.05) were observed in firmness, acidity and pH. Lightness (L*) and redness (a*) of the pulps of non-transgenic and transgenic papaya were similar but varied over the ripening period (P < 0.05). Fruit mass, though non-uniform (P < 0.05) for some lines, was within the range reported for similar papaya cultivars, as were shape indices of female fruits. Transgene proteins, CP and NPTII, were not detected in fruit pulp at the table-ready stage. CONCLUSION: The findings suggest that transformation did not produce any major unintended alterations in the physicochemical attributes of the transgenic papayas. Transgene proteins in the edible fruit pulp were low or undetectable.