A machine-harvestable variety of tomato (the "square tomato") was developed in the 1950s by University of California, Davis's Gordie C. Hanna, which, in combination with the development of a suitable harvester, revolutionized the tomato-growing industry. This type of tomato is grown commercially near processing plants which produce canned tomatoes, tomato sauce, and tomato paste. They are harvested when ripe and are

ue is often used in hostile growing environments, as well as high-density plantings.
Picking and ripening


A cluster of tomatoes
To facilitate transportation and storage, tomatoes are often picked unripe (green) and ripened in storage with ethylene.[32] Unripe tomatoes are firm. As they ripen they soften until reaching the ripe state where they are red or orange in color and slightly soft to the touch.[citation needed] Ethylene is a hydrocarbon gas produced by many fruits that acts as the molecular cue to begin the ripening process. Tomatoes ripened in this way tend to keep longer, but have poorer flavor and a mealier, starchier texture than tomatoes ripened on the plant.[citation needed] They may be recognized by their color, which is more pink or orange than the other ripe tomatoes' deep red, depending on variety.[citation needed]
A machine-harvestable variety of tomato (the "square tomato") was developed in the 1950s by University of California, Davis's Gordie C. Hanna, which, in combination with the development of a suitable harvester, revolutionized the tomato-growing industry. This type of tomato is grown commercially near processing plants which produce canned tomatoes, tomato sauce, and tomato paste. They are harvested when ripe and are flavorful when picked. They are harvested 24/7 during a season of 12 to 14 weeks and are immediately transported to packing plants which operate on the same basis. California is a center of this sort of commercial tomato production and produces about 1/3 of the processed tomatoes produced in the world.[33]
In 1994, Calgene introduced a genetically modified tomato called the FlavrSavr, which could be vine ripened without compromising shelf life. However, the product was not commercially successful, and was sold only until 1997.[34] Slow-ripening cultivars of tomato have been developed by crossing a non-ripening cultivar with ordinary cultivars. Cultivars were selected whose fruits have a long shelf life and at least reasonable flavor.
At home, fully ripe tomatoes can be stored in the refrigerator, but are best kept at room temperature. Tomatoes stored cold remain edible, but tend to lose their flavor permanently.[35] Tomatoes stored stem down may also keep from rotting too quickly.[36]
Genetic modification
Main article: Genetically modified tomato
Tomatoes that have been modified using genetic engineering have been developed, and although none are commercially available now, they have been in the past. The first commercially available genetically modified food was a variety of tomato named (the Flavr Savr), which was engineered to have a longer shelf life.[37] Scientists are continuing to develop tomatoes with new traits not found in natural crops, such as increased resistance to pests or environmental stresses. Other projects aim to enrich tomatoes with substances that may offer health benefits or provide better nutrition.
Consumption



Vegetarian stuffed tomatoes (stuffed with hard-boiled eg