The standard immunoglobulin content of colostrum is ≥10% immunoglobulin (IgG) and ≥40% total protein. Colostrum is best purchased from regular places. Colostrum has the function of regulating intestinal flora and promoting growth and development. It is mainly suitable for non-breastfed infants and children after weaning, as well as pregnant women and so on. Regarding the preservation of colostrum, in colostrum from extrusion to storage not more than 30 minutes, to be refrigerated at minus 18 degrees Celsius, and to be refrigerated at 4 degrees Celsius for transportation. IgG is the highest content in colostrum, and it is also the most critical index to measure the quality of colostrum, and IgG is the core efficacy ingredient of colostrum to improve human immunity. Therefore, IgG content is the key to qualified colostrum.