FlavrSavr
Encyclopedia
Flavr Savr a genetically modified tomato
, was the first commercially grown genetically engineered
food to be granted a license for human consumption. It was produced by the California
n company Calgene, and submitted to the U.S. Food and Drug Administration
(FDA) in 1992. On May 17, 1994, the FDA completed its evaluation of the Flavr Savr tomato and the use of APH(3')II, concluding that the tomato "is as safe as tomatoes bred by conventional means" and "that the use of aminoglycoside 3'-phosphotransferase II is safe for use as a processing aid in the development of new varieties of tomato, oilseed rape, and cotton intended for food use." It was first sold in 1994, and was only available for a few years before production ceased in 1997. Calgene made history, but mounting costs prevented the company from becoming profitable, and it was eventually acquired by Monsanto Company.
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. The modified tomatoes are picked before fully ripened and are then artificially ripened using ethylene
gas which acts as a plant hormone
. Picking the fruit while unripe allows for easier handling and extended shelf-life. Flavr Savr tomatoes could be allowed to ripen
on the vine
, without compromising their shelf-life. The intended effect of slowing down the softening of Flavr Savr tomatoes would allow the vine-ripe fruits to be harvested like green tomatoes without greater damage to the tomato itself. The Flavr Savr turned out to disappoint researchers in that respect, as the antisensed PG gene had a positive effect on shelf life, but not on the fruit's firmness, so the tomatoes still had to be harvested like any other unmodified vine-ripe tomatoes. An improved flavor, later achieved through traditional breeding of Flavr Savr and better tasting varieties, would also contribute to selling Flavr Savr at a premium price at the supermarket.
The FDA stated that special labeling for these modified tomatoes was not necessary because they have the essential characteristics of non-modified tomatoes. Specifically, there was no evidence for health risks, and the nutritional content was unchanged.
. As a result, Calgene's fields produced only 25-50% as many boxes per acre compared to most growers. Of these, only half as many as anticipated were large enough to be sold as premium-priced. Furthermore, much of the initial harvest was damaged during processing and shipping because ripe tomatoes are unavoidably more delicate than unripened ones. Equipment designed for handling peaches was purchased, and specialized shipping crates were developed, both at great expense. These costs along with competition from a new conventionally bred Long Shelf Life (LSL) variety prevented the Flavr Savr from becoming profitable, and Calgene was eventually bought by Monsanto, which was primarily interested in Calgene's ventures into cotton
and oilseed.
produced a tomato paste that used technology similar to the Flavr Savr. Don Grierson was involved in the research to make the genetically modified tomato. Due to the characteristics of the tomato, it was cheaper to produce than conventional tomato paste, resulting in the product being 20% cheaper. Between 1996 and 1999, 1.8 million cans, clearly labelled as genetically engineered, were sold in Sainsbury's and Safeway. At one point the paste outsold normal tomato paste but sales fell in the autumn of 1998.
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. The report identified several possible factors, including product labeling and perception of choice, lobbying campaigns, and media attention. 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 lab 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." In the intervening period, Sainsbury's and Safeway both pledged that none of their house brand products would contain genetically modified ingredients.
Genetically modified tomato
A genetically modified tomato, or transgenic tomato is a tomato that has had its genes modified, using genetic engineering. The first commercially available genetically modified food was a tomato engineered to have a longer shelf life...
, was the first commercially grown genetically engineered
Genetic engineering
Genetic engineering, also called genetic modification, is the direct human manipulation of an organism's genome using modern DNA technology. It involves the introduction of foreign DNA or synthetic genes into the organism of interest...
food to be granted a license for human consumption. It was produced by the California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
n company Calgene, and submitted to the U.S. Food and Drug Administration
Food and Drug Administration
The Food and Drug Administration is an agency of the United States Department of Health and Human Services, one of the United States federal executive departments...
(FDA) in 1992. On May 17, 1994, the FDA completed its evaluation of the Flavr Savr tomato and the use of APH(3')II, concluding that the tomato "is as safe as tomatoes bred by conventional means" and "that the use of aminoglycoside 3'-phosphotransferase II is safe for use as a processing aid in the development of new varieties of tomato, oilseed rape, and cotton intended for food use." It was first sold in 1994, and was only available for a few years before production ceased in 1997. Calgene made history, but mounting costs prevented the company from becoming profitable, and it was eventually acquired by Monsanto Company.
Characteristics
Through genetic engineering, Calgene hoped to slow the ripening process of the tomato and thus prevent it from softening, while still allowing the tomato to retain its natural color and flavor. The tomato was made more resistant to rottingDecomposition
Decomposition is the process by which organic material is broken down into simpler forms of matter. The process is essential for recycling the finite matter that occupies physical space in the biome. Bodies of living organisms begin to decompose shortly after death...
by adding an antisense gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
which interferes with the production of the enzyme
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...
polygalacturonase
Polygalacturonase
Polygalacturonase is an enzyme produced in plants which is involved in the ripening process, and by some bacteria and fungi which is involved in the rotting process. PGs degrades polygalacturonan present in the cell walls of plants by hydrolysis of the glycosidic bonds that link galacturonic acid...
. The enzyme normally degrades pectin
Pectin
Pectin is a structural heteropolysaccharide contained in the primary cell walls of terrestrial plants. It was first isolated and described in 1825 by Henri Braconnot...
in the cell walls and results in the softening of fruit which makes them more susceptible to being damaged by fungal infections. The modified tomatoes are picked before fully ripened and are then artificially ripened using ethylene
Ethylene
Ethylene is a gaseous organic compound with the formula . It is the simplest alkene . Because it contains a carbon-carbon double bond, ethylene is classified as an unsaturated hydrocarbon. Ethylene is widely used in industry and is also a plant hormone...
gas which acts as a plant hormone
Plant hormone
Plant hormones are chemicals that regulate plant growth, which, in the UK, are termed 'plant growth substances'. Plant hormones are signal molecules produced within the plant, and occur in extremely low concentrations. Hormones regulate cellular processes in targeted cells locally and, when moved...
. Picking the fruit while unripe allows for easier handling and extended shelf-life. Flavr Savr tomatoes could be allowed to ripen
Ripening
Ripening is a process in fruits that causes them to become more palatable. In general, a fruit becomes sweeter, less green, and softer as it ripens. Even though the acidity of fruit increases as it ripens, the higher acidity level does not make the fruit seem tarter, which can lead to the...
on the vine
Vine
A vine in the narrowest sense is the grapevine , but more generally it can refer to any plant with a growth habit of trailing or scandent, that is to say climbing, stems or runners...
, without compromising their shelf-life. The intended effect of slowing down the softening of Flavr Savr tomatoes would allow the vine-ripe fruits to be harvested like green tomatoes without greater damage to the tomato itself. The Flavr Savr turned out to disappoint researchers in that respect, as the antisensed PG gene had a positive effect on shelf life, but not on the fruit's firmness, so the tomatoes still had to be harvested like any other unmodified vine-ripe tomatoes. An improved flavor, later achieved through traditional breeding of Flavr Savr and better tasting varieties, would also contribute to selling Flavr Savr at a premium price at the supermarket.
The FDA stated that special labeling for these modified tomatoes was not necessary because they have the essential characteristics of non-modified tomatoes. Specifically, there was no evidence for health risks, and the nutritional content was unchanged.
Fresh tomatoes
The failure of the Flavr Savr has been attributed to Calgene's inexperience in the business of growing and shipping tomatoes. The variety of tomato Calgene started with was considered by farmers to be inferior, and insufficient resources were allocated to traditional plant breedingPlant breeding
Plant breeding is the art and science of changing the genetics of plants in order to produce desired characteristics. Plant breeding can be accomplished through many different techniques ranging from simply selecting plants with desirable characteristics for propagation, to more complex molecular...
. As a result, Calgene's fields produced only 25-50% as many boxes per acre compared to most growers. Of these, only half as many as anticipated were large enough to be sold as premium-priced. Furthermore, much of the initial harvest was damaged during processing and shipping because ripe tomatoes are unavoidably more delicate than unripened ones. Equipment designed for handling peaches was purchased, and specialized shipping crates were developed, both at great expense. These costs along with competition from a new conventionally bred Long Shelf Life (LSL) variety prevented the Flavr Savr from becoming profitable, and Calgene was eventually bought by Monsanto, which was primarily interested in Calgene's ventures into cotton
Cotton
Cotton is a soft, fluffy staple fiber that grows in a boll, or protective capsule, around the seeds of cotton plants of the genus Gossypium. The fiber is almost pure cellulose. The botanical purpose of cotton fiber is to aid in seed dispersal....
and oilseed.
Tomato paste
In the UK, ZenecaZeneca
Zeneca Group PLC was a multinational pharmaceutical company headquartered in London, United Kingdom. Zeneca was formed in June 1993 by the demerger of the pharmaceuticals and agrochemicals businesses of Imperial Chemical Industries into a separate company listed on the London Stock Exchange.In 1999...
produced a tomato paste that used technology similar to the Flavr Savr. Don Grierson was involved in the research to make the genetically modified tomato. Due to the characteristics of the tomato, it was cheaper to produce than conventional tomato paste, resulting in the product being 20% cheaper. Between 1996 and 1999, 1.8 million cans, clearly labelled as genetically engineered, were sold in Sainsbury's and Safeway. At one point the paste outsold normal tomato paste but sales fell in the autumn of 1998.
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. The report identified several possible factors, including product labeling and perception of choice, lobbying campaigns, and media attention. 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 lab rats fed a diet of genetically modified potatoes (see the Pusztai affair
Pusztai affair
The Pusztai affair is a controversy that began in 1998 after protein scientist Arpad Pusztai went public with research he was conducting with genetically modified potatoes. In a short interview he reported that rats fed potatoes engineered to express a plant lectin had stunted growth and a...
). 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." In the intervening period, Sainsbury's and Safeway both pledged that none of their house brand products would contain genetically modified ingredients.
External links
- The Flavr Savr Arrives Article from Access Excellence
- "The transgenic tomato" "Purpose: To show a general reading audience (perhaps readers of a popular science magazine) that genetically engineered crops are needed and safe to consume by discussing the development of a successful genetically engineered crop, the FLAVR SAVR tomato."
- http://www.biotech.iastate.edu/biotech_info_series/bio8.html#anchor259057