Preliminary studies on the microbiological characterization of lactic acid bacteria in suero costeño, a Colombian traditional fermented milk product.

Suero costeño is a fermented milk product from the Colombian Atlantic coast, which is produced by the spontaneous acidification of raw milk due to the action of environmental microbes during traditional and semi-industrial processes. Eleven fermentations were carried out in experimental settings replicating traditional conditions and changes in concentration among microbial groups involved during the process (Aerobic Mesophilic bacteria, Yeasts, Enterobacteriaceae and Lactic Acid Bacteria (LAB)). LAB plays an important role in the fermentation process, especially during the final stage (24 hours). In addition, yeasts seem to have an effect on fermentation, showing an increase during the first hours of the process, while Enterobacterial counts decreased during fermentation. Thirty six LAB strains were isolated from commercial samples and thirty two were identified using the API 50 CH kit (BioMCrieux). 41% of the strains identified belonged to the species Lb. plantarum, and 19% were Lb. paracasei subsp. paracasei. Sugars fermented by LAB include milk carbohydrates such as D-Lactose, D-Glucose and D-Galactose. Because of their capacity to use other carbohydrates (manose, celobiose, maltose, fructose, ribose, trehalose, salicin, gentiobiose), it would also be possible to use these strains as starter cultures for other fermentations.