The superior taste and texture of greenhouse tomatoes is often attributed to the fact that they remain longer on the vine and reach the consumer sooner than field tomatoes. For direct marketers, fruit are harvested virtually red-ripe. For large operations shipping cross-country or even overseas, however, harvest at the breaker stage (first show of color at the blossom scar) is more common. The thin skins and fruit walls of greenhouse cultivars contribute to their appeal to consumers but expose them to injury during harvest and packing. Many large greenhouses have systems designed to protect the fruit and reduce labor costs during harvest. These systems include canals under the greenhouse floor to float the fruit to the packing area and pipe rail systems for wheeling picking carts along the rows and back into the packing area. In beefsteak tomatoes, the calyx and stem are removed at harvest to prevent puncture wounds, except where necessary for marketing purposes. In cluster tomatoes, the entire cluster is cut off at the main stem and kept together either by placing in a single layer in boxes or by putting them into mesh bags.