The natural food color gardenia red is manufactured through the hydrolysis of the methyl ester of iridoid glucoside.One study show that th methanol contents determined at 50 degrees C were 8 and 9 micrograms/g in two gardenia red products and 25-34 micrograms/g in three gardenia blue products, which were below the residual limit of 50 micrograms/g set for many other natural food additives.