Japanese food processors were the first to commercially preserve foods by high pressure. In 1990, these food products included commercially sterile (shelf-stable) jam, yogurt, and pourable salad dressing in 125-g (4.4–oz), hermetically sealed plastic cups. These products had a pH below 4.5 (acid food) to inhibit spore germination, and were treated with pressures in the range of 400 megapascals (60,000 lb/in.²). This treatment was sufficient to inactivate vegetative forms of yeasts, molds, and bacteria when the product was held at pressure for up to 20 min at room temperature. Because high isostatic pressure does not break covalent bonds, the flavors, colors, and nutritive contents of these foods were not changed by the process.