ICUMSA (International Commission for Uniform Methods of Sugar Analysis) is an organization that develops and publishes standards for the measurement and testing of sugar. The ICUMSA 45 specification refers to the measurement of the whiteness of refined sugar. ICUMSA 45 is a measure of the degree of whiteness of a sugar product, with a lower number indicating a higher degree of whiteness. The ICUMSA 45 specification is commonly used in the sugar industry to measure and compare the whiteness of different sugar products. It is typically measured using a spectrophotometer, which measures the amount of light absorbed by a sample of sugar. The ICUMSA 45 specification is used to ensure that sugar products meet certain standards for whiteness, which is an important factor in the quality and appearance of the product