EM stands for Effective Microorganism referring to mixed culture microbial inoculants composed of several species of beneficial microorganism (lactic acid bacteria, photosynthetic bacteria, and yeast). The microorganism live together in symbiosis, each one produces something that is needed by the other one and it is pathogen free. EMs are mainly used as soil amendment or to control waste degradation. EM has been trademarked and is available commercially. But it is often expensive and spoils after some weeks as they are manipulated for commercialisation. Effective microorganisms, depending on the purpose, can also be obtained at home. For lacto-fermentation the easiest way to obtain an effective microbial mix is probably to take an inoculum from sauerkraut (pickled sour cabbage) liquid.