After the formation of the product in the bioreactors, it undergoes through some processes before a finished product to be ready for marketing. The processes include (i) separation and (ii) purification of product which are collectively called the downstream processing The product is subjected to quality control testing and kept in suitable preservatives. If drugs are to be manufactured such formulation has to undergo through clinical trials. A proper quality control testing for each product is also needed. The downstream processing and quality control test are different from product to product