Hello, the authenticity of Shanghai Salt Soda can be distinguished by the following methods:

1. The bottles are different: the bottle of real soda is transparent, while the bottle of fake soda is turbid.

2. The bubbles are different: real soda has fine bubbles, while fake soda has thick bubbles.

3. The taste is different: real soda has lemon flavor, while fake soda tastes sweet.

4. Different colors: real soda is lighter in color, while fake soda is darker.

5. The bottle caps are different: the bottle caps of real sodas are smooth and burr-free, while the caps of fake sodas have burrs.

The above is about how to distinguish the authenticity of Shanghai salt soda. I hope it will be helpful to you.