Preparation of elemental selenium-enriched fermented milk by newly isolated Lactobacillus brevis from kefir grains

A Lactobacillus brevis strain CGMCC No. 6683 that can survive at high selenium concentrations was isolated from kefir grains. Using a scanning electron microscope equipped with an energy dispersive Xray spectroscope, it was shown that L. brevis CGMCC No. 6683 reduced sodium selenite into elemental selenium. L. brevis CGMCC No. 6683 was then pre-treated with sodium selenite to prepare selenium-enriched L. brevis. To study the selenium-enriched yoghurt, selenium-enriched L. brevis was co-fermented in skimmed milk with traditional yoghurt starter culture (Streptococcus thermophilus and Lactobacillus bulgaricus). Results showed that it enhanced selenium concentration in the selenium-enriched yoghurt, and more importantly, elemental selenium was detected in the selenium-enriched yoghurt. The isolated L. brevis provides a new way of preparing a functional dairy product: elemental selenium-enriched fermented milk. (C) 2014 Elsevier Ltd. All rights reserved.