a four-fold rise - Center for Food Safety

Center for Food Safety – Science Comments – FG72 Soybean
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Transgenic contamination resulting from seed mixing can occur in different ways (Mallory-­‐
Smith and Zapiola 2008, Mellon and Rissler 2004). Retailed seeds purchased by farmers can
be contaminated with the transgene, resulting in some fraction of the harvested commodity
containing the trait. After harvest, bulk seeds from different sources are routinely transported,
mixed and stored together, and can result in comingling of different varieties. Human error can
result in mislabeling, failure to follow best practices, and so on (Marvier and VanAcker 2005).
For example, foundation seeds for non-­‐engineered soybeans have been contaminated with
transgenes:
In 2002, the head of North Dakota State University’s Foundation Seedstocks Program
acknowledged that the program’s foundation seed for non-­‐engineered natto
soybeans—the basic stock from which seeds are grown to sell to farmers—contained
sequences from engineered soybeans. [Pates, M. 2002. Seed contamination raises
control issues, posted November 12, 2002. On the Grand Forks Herald website at
http://www.grandforks.com, accessed on January 7, 2003. The article identified
Monsanto’s Roundup Ready soybeans as the source of contamination.] (Natto soybeans
are grown for premium food-­‐grade products.) Three other foundation soybean seed
programs—in Virginia, Missouri, and Michigan—have also recently reported genetic
engineering contamination problems. [The Non-­‐GMO Source. 2003. Concerns increase
over GMO contamination of foundation seed. Volume 3, Number 6, pp. 1-­‐2, June.]
(Mellon and Rissler 2004, p. 10, internal citations included.)
In 2002, Union of Concerned Scientists did a study of transgenic contamination in a sample of
popular non-­‐engineered varieties of soybean seeds from major seed companies available for
planting that year in Iowa and Illinois. They found that at least half of the soybean varieties
tested contained transgenes at levels of less than 0.05 % to more than 1.0 %. These low levels
of contamination nevertheless translate into large numbers of transgenic seeds in the non-­engineered
varieties. For example, if the soybean seed supply is contaminated at the 0.1%
level, over 4 billion seeds would be transgenic (Mellon and Rissler 2004, Table 2-­‐7, p. 29).
In another report, “A Growing Concern: Protecting the Food Supply in an Era of Pharmaceutical
and Industrial Crops” (Andow et al. 2004), UCS enlisted the assistance of several academic
experts in agricultural sciences to determine whether genetically engineered pharmaceutical-­producing
crops could be kept out of food. This report demonstrates how difficult it is, even
for pharmaceutical crops that would be grown on small acreage and under stringent
confinement, to avoid contaminating food. The authors of this report examined confinement
methods, such as field separation, cleaning of farm equipment, segregation of seed, and others,
and found that it would still be difficult to ensure the absence of contamination. Only by
taking heroic measures, such as completely geographically isolating pharmaceutical from food
crops, would contamination be unlikely. UCS concluded that even though it may be
theoretically possible to prevent contamination, it would not be economically feasible.
Another route of contamination that is unpredictable, but likely over time, is human error. Two
academic ecologists address this in a peer-­‐reviewed paper (Marvier and Van Acker 2005), and
conclude that contamination by genetically engineered crops due to human error or other