Color Take an appropriate amount of sample in the white shallow dish on the natural light line, observe, white to light yellow. Taste smell Take an appropriate amount of sample in the white shallow dish in natural light, observe, slightly sweet and odorless. State of organization Take an appropriate amount of the sample in the white shallow disk in natural light, observe, crystal or powder crystal. Lactose a (In the dry basis)/(g/100g) A lactose content according to (100- water-ash)/(100-water) calculation. 99.0 Water/(g/100g) 6.0 (GB 5009.3-2010 Karl fisher method) Ash/(g/100g) 0.3 (GB 5009.4) PH/(10% aqueous solution) Take 10g of lactose in 100ml beaker, add distilled water into 10% water solution,with a pH measuring the value of pH. 4.5-7.0. Conclusion : The quality standard test of this food lactose is in accordance with the regulations.