TOMATO HARVESTING, POST-HARVEST HANDLING AND TRANSPORTATION
Approximately 6.1 million tons of tomatoes are harvested for processing in California each year. Of these nearly 75 percent are handled in tandem truck trailers hauling 26 ton loads. The trailers are towed beside the harvester by large tractors for filling, and are pulled by highway trucks from the field to the cannery which is usually a distance of 100 miles. Unloading is done at the cannery by pulling the trailers onto a 15-degree tilted ramp parallel to a water flume. A five-foot door is opened on the side of the trailer and the fruit is flushed out with a 4-inch stream of water. A filling conveyor was developed to carry the fruit down into the trailer and discharge it at a low velocity onto a spreading deflector to minimize bruising and breaking fruit. The amount of severe damage as indicated by breaks showing visible loculus increases from none in the field to 12 percent at the cannery. Fruit harvested during the hot afternoons has significantly more damage than harvested during the cool morning. All loads are graded for quality. Sampling for grading purposes is accomplished by a device developed by University of California research and manufactured commercially for State Department of Agriculture grading stations. The automated sampler draws a 200-pound core of fruit from top to bottom of the load in an 18-inch diameter cylinder, releasing it over an annulus seperator cone. As the fruit falls in plug flow the center core falls through the annulus hole in the separator cone into a 50-pound sample container while the peripheral fruit near the cylinder wall and the cut fruit are deflected by the cone back onto the truck. Grading is done on mechanical tables that display fruit before inspectors. A microprocessor control unit is being introduced to reduce human error problems with grade certificate printout and computations.
O'Brien, M. (1980). TOMATO HARVESTING, POST-HARVEST HANDLING AND TRANSPORTATION. Acta Hortic. 100, 239-250