They are then size-selected by visual means which is not yet standardized. The next step is undergoing sulphurisation which makes the longan skin yellowish and glowing and can extend the life-span for up to 35-45 days. The taste, however, is not the same as non-sulphurised longan. They smell sulphur and are contaminated with dusts, fungi and pesticides which is extremely hazardous to health.