4.1.1 Wheat should be planted in the natural selenium-rich soil zone of Gaocheng District, comply with the conditions for use of the "Gaocheng Gaoyoumai" geographical indication certification trademark, and comply with the requirements of GB 2715 and GB1351. 4.1.2 Production water should comply with the regulations of GB5749. Sensory requirements Sensory requirements should comply with the provisions of Table 1. Table 1 Sensory requirements Item requirements Inspection method Normal color and smell GB/T5492 Appearance Powder or particulate Take an appropriate amount of sample in a white porcelain plate, observe its appearance with the naked eye under natural light conditions