<prompt> The following tests are used to check the efficiency of pasteurization of milk except:Phosphatase testStandard plate countColiform countMethylene blue reduction test  <response>: The following test have been used to check the efficiency of pasteurization of milk:Phosphatase testStandard plate countColiform count.Dye Reduction Test: Methylene BlueThe methylene blue reduction test is based on the fact that the color imparted to milk by the addition of a dye such as methylene blue will disappear more or less quickly. The removal of the oxygen from milk and the formation of reducing substances during bacterial metabolism causes the color to disappear. 