O-6
Quantification of genetically modified corn in adjuncts using national
standard methods of Japan. In Japan, a negative reaction to genetically modified organisms (GMOs) still
remains strong among consumers. As a consequence, many food manufactures have
made considerable efforts to avoid the use of GMOs as raw materials. Under these
circumstances, Asahi Breweries, Ltd. has adopted several measures since 1999,
including the purchase of cornstarch produced from rigorously segregated non-GM
corn. Labeling Standard for GM Foods has been introduced since April 1, 2001.
Beer is not currently included in the list, but the maximum level allowed for
the contamination of GM materials was set at 5% for non-GM corn. In order to
monitor the distribution by IP handling channel, well-validated quantitative
analytical method had been desired for a long time. Ministry of Agriculture,
Forestry and Fisheries of Japan organized a joint research, in which we also
participated, and developed quantitative methods for GM ingredients. These
methods, based on a real-time PCR with new internal-control molecules for
quantification, have been endorsed as Japanese Standard Methods. In this study,
we evaluated the quantification methods, specifically designed for analyzing 5
lines of GM corns, to determine if these methods are useful for confirming the
authenticity of non-GM cornstarch upon the raw material procurement. DNA
purification method for corn was silica-based as specified by the Standard
Methods, and for cornstarch we also used an anion exchange column to overcome
the low recovery rate and poor purity of DNA. We amplified zSSIIb (endogenous
gene) and specific regions of 5 GM lines (Bt11, Event176, GA21, MON810, T25) by
real time PCR using specific primers and TaqMan-probes. As a quantitative
standard, we constructed a plasmid that includes zSSIIb and 5 GM-specific
regions in its DNA sequence. In order to determine whether the contamination
rates assessed for cornstarch are consistent with those of the original corn, we
compared the data obtained from these two samples. As a result, the
contamination rates calculated for both samples were shown to be in good
agreement, indicating that the authenticity of non-GM cornstarch can be
inspected upon the procurement of raw materials.
Tomoaki Yoshimura received a master's degree in Agricultural Chemistry
from Chiba University. He began employment with Asahi Breweries, Ltd. as a
biochemist in 1991. From 1991 to 1999, he was engaged in the research of
Neuroscience and Oncology. Since 1999, he has researched Food Safety including
GMOs, and has worked with Dr. Hino at National Food Research Institute of Japan
in developing the quantification methods. He is now an assistant section manager
of Safety Evaluation Section.
TOMOAKI YOSHIMURA, Yoichiro Shindo, Koichi Harayama, Naoki Mochizuki, and
Hiroshi Yamashita. Analytical Technology Laboratory, Asahi Breweries, Ltd.,
1-1-21, Midori, Moriya, Ibaraki, 302-0106, Japan.