Use of Maldi-Tof MS biosensor in microbial assessment of Brazilian kefir grains

Roberta Oliveira Viana,Rosane Freitas Schwan,Disney Ribeiro Dias,Karina Teixeira Magalhães-Guedes

doi:10.1590/0034-737x201966010010

Roberta Oliveira Viana, Rosane Freitas Schwan + Show 2 more

Open Access

https://doi.org/10.1590/0034-737x201966010010

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Abstract

ABSTRACT The aim of this study was to evaluate the use of Maldi-Tof MS biosensor in microbial assessment of Brazilian kefir grains. Maldi-Tof MS is a new methodology for the rapid diagnosis of microorganisms. A total of 358 microorganisms were isolated, 31 were yeasts and 327 were bacteria (divided into lactic and acetic bacteria). Microbial colonies were grown in Luria-Bertani agar medium and incubated at 35 °C for 18h and used in the identification of species by Maldi-Tof MS. The microbial population identified in Brazilian kefir grains was Lactobacillus paracasei, Saccharomyces cerevisiae, Lactobacillus plantarum, Acetobacter pasteurianus, and Acetobacter syzygii. This study demonstrated a rapid and accurate identification of the Brazilian kefir grains microorganisms using the Maldi-Tof MS biosensor. In conclusion, the Maldi-Tof MS technology can facilitate the microbiological control in a fermentation process using kefir grains as starter cultures.

Highlights

Kefir is a polysaccharide grain containing microorganisms that produce fermented beverages, such as the traditional Turkish beverage named “kefir”, which is from milk, and has low alcohol content (Simova et al, 2002; Guzel-Seydim et al, 2005; Irigoyen et al, 2005; Magalhães et al, 2011a, 2011b, 2011c; Puerari et al, 2012; Cho et al, 2018)
The microbial population count of the kefir grains performed in this study Found: lactic acid bacteria with a population of 8.10 log CFU mL-1; Acetic acid bacteria (AAB) in a low population of 4.01 log CFU mL-1; and yeasts in population of 6.01 log CFU mL-1
The results showed higher population of Lactobacillus paracasei (106 CFU mL-1); Saccharomyces cerevisiae, Lactobacillus plantarum, Acetobacter pasteurianus, and Acetobacter syzygii were found in smaller quantities (104 CFU mL-1) (Figure 2)

Summary

Introduction

Kefir is a polysaccharide grain containing microorganisms that produce fermented beverages, such as the traditional Turkish beverage named “kefir”, which is from milk, and has low alcohol content (Simova et al, 2002; Guzel-Seydim et al, 2005; Irigoyen et al, 2005; Magalhães et al, 2011a, 2011b, 2011c; Puerari et al, 2012; Cho et al, 2018). The grains are responsible for the fermentation that produce lactic acid, acetic acid, CO , alcohol (ethyl 2 alcohol), and aromatic compounds. These compounds provide the unique sensory characteristics of kefir: fizzy, acid taste, and tart and refreshing flavour (Corona et al, 2016)

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