Advances in microbiology have made preservation techniques more applicable to new products. As a result, certain purified and effective kinds of microbes are utilized in food preservation. Products such as soy sauce and bean paste are often produced at the same time because they both use fungi spores called the Aspergillas Flavus Columnaris as an ingredient, in order to prevent contamination by other fungi and to make soy sauce stay in good quality throughout the year. More importantly, the fungi spores used do not generate aflatoxin which is a carcinogen.