Always use a clean spoon. The acidity of the paste will change and deteriorate in a shorter period when your mix your meals with a clean spoon. Mold spores, which are not visible to the eye, come from the spoon and found in the air. Its starts reproducing by mixing into the paste. Mold spores break down the sugar, which contains in the paste, forms acid, and multiply. You can see them on the paste in layers of green and white.