For quality assurance and to safeguard the availability of its products all year round, the GNT Group, the leading international supplier of coloring foods, checks and monitors every link in the value-added chain. The crops GNT uses are grown exclusively in the area around the German/Dutch border. Their cultivation and harvesting is managed by its in-house agricultural engineers. The company provides its customers with comprehensive advice on all aspects of the stability, color, and shelflife of the products they select. Light can affect product stability. To assure the high quality of the concentrates, the various foodstuffs and beverage applications undergo extensive photostability testing (among other types of test) in the company's own application centers. These tests verify that the products will retain their properties throughout their useful lives. They also enable the stability of the products to be compared in various enduse applications. Specific in-country climactic conditions are taken into account and, depending on the relevant application, some of the tests are even carried out under controlled moisture conditions.