n they are either consumed in conjunction with foods, or when they are consumed in large quantities. At times, such poisoning is fatal to humans.
Once a processed food product has been sterilized and cooled, it must be placed into a sterile container for delivery to the consumer. Both the process of placing the product into the container, and the container itself must be sterile. Fur ther, the container must be capable of maintaining the product in a sterile condition for at least the intended shelf life of 3the product. Both the food container and its cover, thus, must be made of materials which are both impermeable and non absorb ent. Further, such containers should not permit the leaching of chemicals or elements from the container into the food pro duct.
There are five major aseptic packaging systems. The five systems are (1) metal containers and closures, (2) flexible packages from continuous roll tube stock, (3) flexible pack ages from continuous roll drum stock, (4) preformed plastic cups, and (5) thermoform fill seal. Each of these five major aseptic packaging systems is described in the discussions which follow.
The metal containers and closures system sterilizes the containers and closures by heat obtained from superheated steam. Superheated steam is a dry heat, which is produced by heating saturated steam to high temperatures. This heat medium may be used at atmospheric pressures, whereas saturated steam may not be used at such pressures. A major disadvantage to superheated steam is that microbial organisms have a greater resistance to dry heat than they do to wet heat. Thus, far higher temperatures (around 204 degrees Celsius) are required to sterilize with superheated steam.
Effective sterilization using superheated steam is a func tion of both time and temperature. The length of the sterili zation process is dependent upon (1) the number of sterilizing
tunnels, (2) the length of sterilizing ...