| 摘要 |
PURPOSE:To prevent the degradation and discoloration of the content in a retort pouch with oxygen, by carrying out the pressurization of the retort by introducing a pressurizing medium composed of an inert gas such as nitrogen gas. CONSTITUTION:A retort pouch is put into a retort, and steam is introduced into the retort to replace the air in the retort with steam and to decrease the residual oxygen content in the retort to a negligibly low level. A nitrogen bomb of about 150kg/cm<2> is connected to the retort, and the pressurized nitrogen is introduced into the retort at a proper timing. The inner pressure of the retort is increased by decreasing the amount of the exhaust gas, and the temperature of the atmosphere in the retort is raised to >=100 deg.C, preferably >=120 deg.C. Thereafter, the feeding rates of steam and nitrogen are adjusted to proper levels, and maintained to the levels for a definite time interval to effect the sterilization. The degradation and discoloration of the content in the retort pouch caused by oxygen can be prevented by this process. |
