Separation of viable lactic acid bacteria from fermented milk. Issue 4 (April 2018)

• Record Type: Journal Article
• Authors: Nishino, Tomohiko; Matsuda, Yusuke; Yamazaki, Yuna
• Is Part Of: Heliyon. Volume 4:Issue 4(2018)
• Publication Date: 2018-04
• Subjects: Food analysis -- Microbiology; Research -- Periodicals; Medical sciences -- Periodicals; Natural history -- Periodicals; Social sciences -- Periodicals; Earth sciences -- Periodicals; Physical sciences -- Periodicals; 507.2
• DOI: 10.1016/j.heliyon.2018.e00597
• Languages: English
• ISSNs: 2405-8440

Abstract

Abstract: Probiotics are live microorganisms that provide health benefits to humans. Some lactic acid bacteria (LAB) are probiotic organisms used in the production of fermented foods, such as yogurt, cheese, and pickles. Given their widespread consumption, it is important to understand the physiological state of LAB in foods such as yogurt. However, this analysis is complicated, as it is difficult to separate the LAB from milk components such as solid curds, which prevent cell separation by dilution or centrifugation. In this study, we successfully separated viable LAB from yogurt by density gradient centrifugation. The recovery rate was >90 %, and separation was performed until the stationary phase. Recovered cells were observable by microscopy, meaning that morphological changes and cell viability could be directly detected at the single-cell level. The results indicate that viable LAB can be easily purified from fermented milk. We expect that this method will be a useful tool for the analysis of various aspects of probiotic cells, including their enzyme activity and protein expression.