To address this, tomatoes intended for shipping are often picked while they are unripe, or "green", and then prompted to ripen just before delivery through the use of ethylene gas, which acts as a plant hormone.
[6] Calgene scientists used the modified bacterial parasite Agrobacterium tumefaciens to transfer genetic material into Flavr Savr plant cells.
[2] The Flavr Savr was made more resistant to rotting by the addition of an antisense gene which interferes with the production of the enzyme beta polygalacturonase.
The enzyme normally contributes to spoilage by degrading pectin in cell walls and results in the softening of fruit, which makes them more susceptible to being damaged by fungal infections and physical actions.
Flavr Savr turned out to disappoint researchers in that respect, as the antisense version of the PG gene had a positive effect on shelf life, but not on the fruit's firmness.
[11] Most GMOs were not subjected to mandatory labeling, which allowed for the vast majority of commercially sold, genetically modified foods to remain unlabeled.
[citation needed] Some chefs and food distributors boycotted the Flavr Savr and refused to sell the tomatoes in their stores.
Between 1996 and 1999, 1.8 million cans, clearly labelled as genetically engineered, were sold in the major supermarket chains Sainsbury's and Safeway UK.
The House of Commons of the United Kingdom published a report in which they stated that the decline in sales during this period was linked to changing consumer perceptions of genetically modified crops.
It concluded that the tone of media reports on the subject underwent a "fundamental shift" in response to a high-profile incident in which Dr. Arpad Pusztai, a researcher for Rowett Research Institute, was fired after making a televised claim about detrimental health effects in laboratory rats fed a diet of genetically modified potatoes (see the Pusztai affair).
Subsequent peer review and testimony by Dr. Pusztai led the House Science and Technology Select Committee to conclude that his initial claim was "contradicted by his own evidence."