I can't tell what country you are from; but in the USA there is a product, called RealLemon and RealLime, that was successful for me and several other posters here. It comes in a little plastic bottle the size of a lemon. Also, they have it in a glass bottle. We did not worry about the small amount of preservative. It had its own dropper; but most people measured it by the 1/4 teaspoon or so. It worked and could be kept in the refrigerator for a long time.