In the traditional food canning process, the filled aluminium or tinplate cansare hermetically sealed, with can ends attached by a double seaming operation,and the cans heated in a batch retort. Heating is usually achieved by steam orwater, and care must be taken to ensure that the heat penetrates to the slowestheating point in the can, so that no part of the food is left under-processed. Atthe same time, it is desirable not to overcook the food, as this will result in44 FOOD PACKAGING TECHNOLOGYreduction in the quality of the food. A metal can is the ideal package from aprocessor’s perspective because, relative to other packaging media, it offers thepossibility of high production speeds, as well as good pack size flexibility, andthe high compression strength of cans enables them to withstand physicalabuse during processing and distribution. The metal can offers a high degree ofreliability of pack integrity throughout the distribution chain as well as highspace efficiency in warehouse storage due to the feasibility of high palletstacking. In contrast to thicker plastic and glass packs that permit slower heattransfer, the thin-walled metal can is a good conductor of thermal energy fromthe heating and to the cooling media.
đang được dịch, vui lòng đợi..
