The most outstanding innovation in vapor heat technology was the development of so-called differential pressure treatment system which expanded the scope of vapor heat application to a wide range of fresh fruits. Treatment system of this type uses differential pressure to induce efficient circulation of vapor heat through all spaces in-between fruits so that every each individual fruit is always evenly and uniformly exposed to vapor heat atmosphere. The most sophisticated system which was developed by Japanese manufacturers is equipped with high-technology instruments, high-precision temperature sensors as well as built-in computers to control temperature exactly at 0.1 level and humidity at 1% level. At present, almost all fresh fruits being imported to Japan on the condition of VHT are processed with differential pressure type treatment system.