The aim of TS is new foods development by using sustainable substrates and fermentation technologies. Considering problems, assotiated with the unused food by-products, the possibility of re-utilizing / valorisation it in the food chain become very important. During the TS will be showed technologies, that the valorization of dairy and cereal by-products can be very promising for the sustainable antimicrobial biomass preparation and further high quality food development in sustainable manier. On the scope of the Working Group 7 (WG7) of the COST Action 18101, SOURDOMICS, the aim of this TS is to offer theoretical and practical training to those members of SOURDOMICS that showing interest to deepen knowledge of the by-products valorization, as well as new products development and analysis. This TS will encompass a practical training in the Department of Food Safety and Quality (Lithuanian University of Health Sciences), situated in the Campus of the Faculty of Veterinary Medicine. More details at http://www.lsmuni.lt/en/. The TS will encompass all equipment for the TS aim implementation (HPLC and GC technique, all equipments to perform microbiological analysis etc.). Also, collection of the pure lactic acid bacteria, for the new products development, as well as cereal and dairy industry by-products, will be provided. Trainees will be asked to select by-product type, with which they would like to work during the TS (dairy or cereal industry by-products). Methodology for the valorization and new product development will be suggested and methodical part for all the experiments planed. After the TS, trainees will be asked to write a report about the results obtained, which further will be used for the joint scientific publication preparation.