A study of organic and conventionally grown processing tomatoes by a team of researchers at the University of California, Davis, indicated that, on the four participating commercial farms, organically produced tomatoes were higher in sugars and other soluble solids, consistency and acidity, all of which are desirable attributes in processing tomatoes. The organically grown tomatoes were lower, however, in red color, vitamin C and certain healthful compounds known as phenolics.

Results from the study, which appear in the November-December issue of the Journal of Food Science, varied significantly among the growers, perhaps due to differences in soil type, soil nutrients, tomato varieties, environmental conditions and production methods.

"It is important to evaluate successful production systems in a realistic environment," said lead researcher Diane Barrett, a Cooperative Extension food scientist at UC Davis. "But it is often not possible to control all variables when a study is conducted as part of a commercial farming operation.

"Because there were only four growers involved in the study and because there were differences in growing practices between the four growers, we aren't able to make global statements about the comparative quality and nutritional value of organically grown and conventionally grown processing tomatoes," Barrett said.

She noted, however, that the study did underscore how critically important the plant genetics, soil nutrients, irrigation system and production inputs are in determining the quality of the fruit produced.

The researchers hope that future studies will include a larger number of commercial growers, so that the resulting data will yield more statistically valid conclusions about the global differences between organic and conventionally grown tomatoes. They also hope to correlate their findings from studies conducted as part of commercial operations with findings from studies carried out on university research plots, where production methods can be better controlled.

The four commercial farms participating in the study were experienced in using both organic and conventional methods to grow processing tomatoes. The farms were operated by Harris Farms Inc., Terranova Ranch Inc. and O'Neill Farming Co. Inc, all of Fresno County; and D.A. Rominger and Sons Inc. of Yolo County.

This study was supported by Small Planet Foods.