1. The bar code on the food also belongs to commodity bar code. This is a one-dimensional bar code. One-dimensional bar code refers to the arrangement rules of bar code and space. The commonly used code systems of one-dimensional code include EAN code, 39 code, crossed 25 code, UPC code, 128 code, 93 code, ISBN code and Codabar code.

2. Barcode originated in the 1940s, was applied in the 1970s and became popular in the 1980s. Bar code technology is an automatic identification technology which is produced and developed in computer application and practice. It is widely used in business, postal service, book management, warehousing, industrial production process control, transportation and other fields. It has the advantages of fast input speed, high precision, low cost and strong reliability, and plays an important role in today's automatic identification technology.

3. Barcode is a mark composed of a set of regularly arranged bars, spaces and corresponding characters. "Strip" refers to the part with low light reflectivity, and "empty" refers to the part with high light reflectivity. The data composed of these bars and spaces express certain information, which can be read by special equipment and converted into binary and decimal information compatible with computers.

Usually, the code is unique for each project. For ordinary one-dimensional bar code, the corresponding relationship between bar code and commodity information should be established through the database. When the barcode data is transmitted to the computer, the application programs on the computer will operate and process the data.

Therefore, the ordinary one-dimensional bar code is only used as identification information, and its significance is realized by extracting the corresponding information from the database of the computer system. One-dimensional bar code is simple to make, and the coding system is easy to be obtained and forged by criminals. Secondly, it is almost impossible for one-dimensional bar codes to represent Chinese characters and image information.