The University of California, Davis, is recalling about 30 tomato seed samples, distributed during the past seven years to research colleagues in the United States and abroad, after recent tests showed that the seed was not the intended variety, but rather a very similar variety developed through biotechnology.

The seed contains a commercially approved biotech trait, referred to as the PG trait. That trait, which improves the thickness of tomato paste, had been approved in 1994 for use in human food. A similar tomato variety with the PG trait had previously been planted commercially in California, and tomato paste with the trait had been sold to consumers, primarily in the United Kingdom.

The Seed and Its Distribution

Since 1996, small quantities of seed of the processing-tomato variety known as UC-82B were provided, upon request, by UC Davis to researchers at 12 institutions in the United States and to researchers in 14 other countries. Each sample included about 25 seeds to be used in research projects at those institutions. Two samples were also sent abroad for demonstration gardens in England and Ethiopia. UC Davis and the recipients were unaware that these particular UC-82B seeds carried the PG trait.

UC Davis officials have determined that the seeds carrying the PG trait originated from a 20-gram seed sample donated to UC Davis in 1996 by Petoseed Company, which has since been acquired by Seminis Vegetable Seeds. It is unclear when or where the seeds were mislabeled.

The seed mix-up came to light when the Charles M. Rick Tomato Genetics Resource Center at UC Davis sent samples of what was thought to be unmodified UC-82B to the UC Davis Plant Transformation Facility. This research service unit genetically modifies small numbers of plants for use in campus research projects. In working with the seeds, staff scientists detected the unexpected presence of a commonly used "marker" gene, NPT II, and notified the Rick center. The protein derived from the NPT II gene has been approved by the U.S. Food and Drug Administration as a food additive. Subsequent testing also revealed the presence of the PG gene.

A similar tomato variety with the same combination of PG gene and NPT II was commercialized in 1996 through a collaboration between Petoseed Company and Zeneca Plant Science. That variety was approved for food and tomato production in the U.S. by the Food and Drug Administration in 1994 and the U.S. Department of Agriculture in 1995. It also was approved for food consumption by the government of the United Kingdom in 1995 and in Canada by Health Canada in 1996. That variety also passed scientific review in the European Union. It was grown commercially in California and sold as tomato paste product in the United Kingdom between 1996 and 1999.

Response by UC Davis and Seminis

Upon learning of the apparent mix-up, the Rick tomato center curator reviewed records and found that the UC-82B seed had been obtained in 1996 from Petoseed. Although that seed variety had been developed in 1976 by a UC Davis plant breeder, the campus supply had run low and Petoseed had replenished it.

"We immediately tested our seed and informed both Seminis and the U.S. Department of Agriculture," said Neal Van Alfen, dean of UC Davis' College of Agricultural and Environmental Sciences. "DNA sequencing conducted at UC Davis has confirmed the presence of the PG trait.

"We have notified the individuals or research units that received the seed," Van Alfen added. "We are asking the recipients to let us know how they used or disposed of the seed, and to send any seeds remaining from the original sample to an independent laboratory for DNA testing."

Ed Green, senior vice president of research and development at Seminis, said: "We will continue to work closely with the university to determine how this error occurred. We have offered the full analytical resources of Seminis and have made our records available to university officials.

"While current regulatory controls and technological advances would make this type of mix-up highly unlikely today, we also feel it's prudent to review our seed handling, storage and sharing protocols to look for improvements, " Green said.

Green added that only a small fraction of Seminis' current research involves biotechnology because the company's focus is on traditional plant breeding. Seminis does not sell any tomatoes developed with biotechnology.

Background on the Rick Center and Seminis

UC Davis' Charles M. Rick Tomato Genetics Resource Center is associated with the National Plant Germplasm System. Upon request, the center provides seed samples to scientists and educators worldwide. The center houses seeds of more than 3,600 wild species and domesticated varieties, and is considered the most diverse collection of its kind in the world.

Seminis markets more than 4,000 vegetable and fruit varieties. Its products reduce the need for chemical pest controls, improve grower yields and offer improved nutrition, flavor and convenience, according to Seminis officials.