Separation of viable lactic acid bacteria from fermented milk

Area of Science:

• Microbiology
• Food Science

Background:

• Probiotics, including lactic acid bacteria (LAB), offer health benefits.
• LAB are crucial in fermented foods like yogurt, but their analysis is challenging due to milk components.
• Understanding LAB's physiological state in food matrices is vital for probiotic efficacy.

Purpose of the Study:

• To develop an effective method for separating viable LAB from yogurt.
• To enable single-cell level analysis of LAB in fermented milk.

Main Methods:

• Density gradient centrifugation was employed to isolate viable LAB from yogurt.
• The separation process was optimized and assessed for recovery rate and efficiency.

Main Results:

• Successful separation of viable LAB from yogurt with a recovery rate exceeding 90%.
• Separated LAB were observable via microscopy, allowing for direct single-cell analysis.
• The method proved effective for purification until the stationary phase.

Conclusions:

• Viable lactic acid bacteria can be efficiently purified from fermented milk using density gradient centrifugation.
• This method facilitates detailed analysis of probiotic cells, including enzyme activity and protein expression.
• The technique offers a valuable tool for studying probiotic functionality in food products.