This simplified guide shows in color some of the major types of can defects which may be commonly found by visual observation. It categorizes the defects/damages according to their degree of potential hazard, and shows what to look for in the routine visual inspection of the finished product. These classifications may change after laboratory examination. It is essential that prior to sale, samples of each defect suspected of causing loss of hermetic seal be collected for laboratory examination, i.e. measurement and integrity of can seams, microbiological analysis of contents, etc. Note that a “hermetically sealed” container for canned food and/or beverages is considered as one that is appropriately constructed/designed and intended to assure no entry of bacterial microorganism and thus maintain the commercial sterility of its contents after thermal processing. Other definitions commonly and frequently used in the visual evaluation of can defects are included as part of this guide for a quick and simple reference and for use in the field.