In the present work, the extraction and detection of DNA along a complete industrial soybean oil processing
chain was described to monitor the presence of Roundup Ready (RR) soybean. The analysed samples
comprised all the steps prior to industrial oil extraction, namely, raw, cracked, laminated and expanded
seeds, and the defatted flour as a sub-product. The samples collected at the refining unit included the
crude oil, degummed/neutralised, washed, bleached and deodorised oil, as final product. The amplification
of soybean lectin gene by end-point polymerase chain reaction (PCR) was successfully achieved in all
the steps of extraction and refining processes, until the fully refined soybean oil. The amplification of RR
soybean by PCR assays using event-specific primers was also achieved for all the extraction and refining
steps, except for the intermediate steps of refining (neutralisation, washing and bleaching) possibly due
to sample instability. The real-time PCR assays using specific probes confirmed all the results and proved
that it is possible to detect and quantify genetically modified organisms in the fully refined soybean oil.
To our knowledge, this has never been reported before and represents an important accomplishment
regarding the traceability of genetically modified organisms in refined oils.
