Development and Application of a Nested Polymerase Chain Reaction Method for the Detection of Genetically Modified Soybean in Chinese Traditional Fermented Soy Food-sufu

CHIA-CHIA HUANG, TSUNG-WEI SHIH AND TZU-MING PAN*

Institute of Microbiology and Biochemistry, National Taiwan University, 1, Sec. 4, Roosevelt Rd., Taipei 106, Taiwan, R.O.C.

(Received: March 12, 2004; Accepted: June 2, 2004)

ABSTRACT

   A nested PCR method has been developed to distinguish traditional soybean from transgenic Roundup Ready soybeans (RRS).  Comparing with the standard PCR method, the nested PCR method increases the sensitivity by 200 to 1000-fold. One copy of RRS genome can be detected by the nested PCR. Sufu, a traditional fermented soybean curd, is a very important Chinese condiment and it is a highly processed food. We have used the nested PCR to detect seven time points of sufu throughout the aging period. The nested PCR method showed positive results for sufu made up of 100% RRS at all seven time points from 0th day to 180th day. This work describes the development and application of a sensitive and specific detection method for sufu made from RRS using a nested PCR system.

Key words: genetically modified organism (GMO), Roundup Ready soybean (RRS), sufu, fermented food, detection, polymerase chain reaction (PCR), nested PCR