Nestle has stopped buying any grain from genetically altered seed for its European operations.
So it is not surprising to find some outside presence of genetically altered seeds in bags meant to contain nonengineered varieties.
The company has also come under sharp criticism, especially in Britain, for its genetically altered seeds.
Monsanto's biotechnology traits are used in nearly all the genetically altered seeds now on the United States market.
The most contentious issue was the establishment of a notification system for foods produced with genetically altered seeds.
The altered seeds would be cultivated as soon as the geneticists and the agriculturists were done tinkering with them.
Analysts estimate that more than $10 billion worth of genetically altered seeds have been sold in the United States since they were commercialized in 1996.
Before it realized how successful altered seeds would be, Monsanto sold the technology to some companies, including Pioneer, for relatively modest sums.
Scientifically altered seeds already account for huge parts of the United States cotton, soybean and corn crops.
The treaty allows countries to bar imports of genetically altered seeds, microbes, animals and crops that they deem a threat to their environment.