Does anyone have professional experience or advice on the safety of Kombucha? My son makes it and I wonder!?

This is suppose to be very very healthy from what he tells me, but I get a little concerned about the bacteria in that growth thing in it called "mushroom". It grows and he lets it sit for days before bottling it and separating parts of the mushroom to make more of the drink. It can be bought in health food stores, but I'm feeling unsure about this mixture. Thoughts, suggestions, any food specialists or medical doctors that can answer my concern?? Thanks bunches!

Kombucha has been around for a long time, indeed probably hundreds of years or more. Many Asians believe it gives health. It's a complex mixture of bacteria and yeast called a SCOBY (symbiotic culture of bacteria and yeast, NOT a mushroom) that produces compounds that cause the body's immune system to "wake up". It also has compounds such as glucuronic acid which some believe help to chelate bad heavy metals and other things. At any rate, I've been drinking it for about a month now, with no problems. It seems to make me more relaxed, generally. I drink a small amount, about 4 ounces, twice a day. I don't think people should drink large quantities daily, because it is acidic (like apple cider vinegar) and thus could change the body's PH if overused. I also take a break from it now and then. He can refrigerate the separated "babies" with some of the liquid if he wants to stop making it for awhile, and then come back to it. It's important that each step of the tea making process is clean, and that the tea isn't exposed to external molds while growing (I use 2 coffee filters rubber banded to the top of the jar). If any fuzzy mold grows on the top of the culture, the whole thing must be thrown out. I guess my bottom line is: It shouldn't hurt him if he is making it well and not drinking too much (like liters daily or something). It's been around a long time and many people swear by its health benefits. See link below.