I'm forwarding this writeup as I know the dried Chinese black mushrooms are often used in Chinese dishes, liking it a lot myself.
Subject: Dried black mushrooms from China
Email from Fred Chin, one of our Chinatown old timers
I just had some dried black mushrooms and fortunately drained the soak water. It has been found that Mushrooms from China contain carbon disulfide in them. Not sure what this chemical does if consumed and the amount of concern. So I googled to do a quick check out and found that carbon disulfide is a pesticide/ fungicide with acceptable/legal residue levels defined for fresh/dried foods. Anyway, safest is to dump the soak liquid and not use it in the cooking process.
China's regulations are questionable. This message is toward you against using the water you soak your mushrooms in.
Most of the mushrooms on the market are from China, and are contaminated with chemicals (I think it is carbon disulfide, or disulfide, (correct me if I am wrong) which are soluble in water. You must discard the water that you soak the dried mushrooms in to soften it.
According to Mr. L.W. Chan of the Health Department, most mushrooms were smuggled into the country from China. The recent opening of traffic between China and Taiwan made it difficult for the government to control these illegal activities.
We can only suggest that we should best use Taiwanese mushrooms or Japanese Shiitake Mushrooms. It is advisable to soak them in water before cooking and the water used to soak the mushrooms must be thrown away. Mr. Chan continued to say that it is customary and a common practice for people to cook the mushrooms with the water saved from soaking. This habit should stop, because most fertilizers used in farming were water soluble.We still do not know the outcome of how the Japanese are looking at our research but according to their tests in the past, it was known that the mushrooms were contaminated by the fertilizer.
Mushrooms originally contained sulfur and when mixed in with fertilizer, the carbonate test showed a 20% higher reading on carbon disulfide which made it difficult to obtain a reliable reading on results.
Guys, please forward this to your wives, daughters, girlfriends, family, and others you know who use dried black mushrooms.
** Sulfide has potential to cause allergy, mostly asthmatic. 10% of asthma cases are cause by allergy to sulfides. It is a preservative, but strictly regulated.
