I don't understand why the processing times for tomatoes are so long. Aren't they an acid food?
Actually, where home-canning is concerned, tomatoes are right on the borderline between low-acid vegetables and acid fruit. Some of the newer tomato varieties have an increased sugar content and a decreased amount of acid. These factors were taken into consideration when the processing times for tomato products were researched.
Barbara Willenberg, Nutritional
Sciences, University of Missouri-Columbia
Last update: Tuesday, May 05, 2009