cooked soy beans and roasted wheat are mixed together. the mixture is fermented by the asperilligus fungus. the mixture is then fermented by yeastes. the mixture is fermented again by the lacto bacillus bacterium. finnaly it is pasteurised to kill of harmful micro-organisms and packaged.
First the soya beans are cooked, killing the bacteria on the surface and are mixed with ground roasted wheat.
Next Aspergillus mould is added. The mixture is spread out large warm shallow trays and are given air.
The Aspergillus mould creates enzymes that act as a catalyst for (speed up) the breakdown of the proteins and carbohydrates in the mixture. This increases the amounts of amino acids and sugars in the mixture.
Brine is added to the solution. This creates the salty taste in the sauce and preserves it.
Now yeasts and lactobacillus bacteria are added. These stop the aspergillus moulds activity and they also ferment the sugars in the solution.
The sauce is filtered.
Then pasteurised (at 72C) and stored. Then it is sold!
Its pretty much all copied from the textbook! But I hope it helps!