Flavr Savr, a genetically modified tomato, was the first commercially grown genetically engineered food to be granted a license for human consumption. The Flavr Savr was made more resistant to rotting by adding an antisense gene which interferes with the production of the enzyme polygalacturonase. The enzyme normally degrades pectin in the cell walls and results in the softening of fruit which makes them more susceptible to being damaged by fungal infections. Antisense technology is a tool that inhibits gene expression. The antisense nucleic acid sequence base pairs with its complementary sense RNA strand and prevent it from being translated into a protein.