In commercial practice, the fermentation starters and processes are usually controlled to standardize the final products. In these cases, a controlled process involves heavy inoculation of the desired microorganism and adjustment of pH, nutrient, temperature, and time conditions to favor the main fermentation and to suppress the growth and metabolism of the natural flora. Optimal temperatures for fermentation are usually well known by practitioners. Media composition vary widely, and some guidelines are usu-TABLE 2 Continuedally given depending on expected results. For example, concentrations of water and salt are usually specified for best results. Cereal fermentations are anaerobic by nature, but in some cases such as in soy sauce production, a slight mixing of fermenting medium to incorporate some oxygen is recommended for accelerating mold activity. Adjustment of pH might be necessary in some cereal fermentations, but the widespread presence of lactic acid bacteria in cereals normally contributes to the rapid lowering of the pH.