Читать книгу Foods and Their Adulteration - Harvey Washington Wiley - Страница 61

—After the cans are filled in this way and closed by soldering or otherwise they are placed in retorts which are composed of strong iron or steel boilers, properly covered and secured, and when these boilers are full they are subjected to the action of steam heat under pressure. Usually a small hole is left in the can through which any gas, air or other kind, is expelled from the can. As soon as everything is complete the retorts are opened and the cans are sealed.

In all cases, however, after sealing the cans they are subjected to a second heating at a temperature of from 225 to 250 degrees F. The time of heating varies from one to two hours. After removal from the retorts the cans are washed with a spray of cold water for several hours, and they are then dried, painted, and labeled.

The above is a general description of the process employed which, however, is varied to some extent in different packing houses.

A modification of the above method consists in exhausting the cans in vacuo and automatically sealing them in the exhausted state, thus removing all air and other gases therefrom. The cans are then placed upon an endless conveyor and dipped into an oil bath at a temperature of 240 degrees, the speed of the conveyer being so regulated that the cans remain in the bath a sufficient length of time to complete sterilization before being carried out at the opposite end. After passing through this bath they are carried automatically into another bath consisting of a solution of carbonate of soda and, finally, into a bath of pure water. The cans are then painted and labeled as originally described.