Diversity of lactic acid bacteria in vegetable-based and meat-based fermented foods produced in the central region of Vietnam

Yen Thi Ngoc Phan,Tu Thi Minh Tran,Trang Hien Nguyen,Naoki Nishino,Van Huu Nguyen,Takeshi Tsuruta,Minh Thuy Tang

doi:10.3934/microbiol.2017.1.61

Abstract

The diversity of lactic acid bacteria (LAB) in naturally fermented foods produced in Hue, a city in the central region of Vietnam, was examined. From local markets, a total of 25 samples of three vegetable-based fermented products, specifically dua gia (bean sprouts), dua cai (cabbage), and mang chua (bamboo shoots), and two meat-based fermented products, specifically nem chua (uncooked pork) and tre (cooked pork) were obtained. The LAB diversity was assessed by quantitative real-time polymerase chain reaction (PCR) and qualitative denaturing gradient gel electrophoresis. Lactic and acetic acid contents were greater in meat-based products than in vegetable-based products. Major LAB species found in vegetable-based products (Lactobacillus plantarum, Lactobacillus fermentum, and Lactobacillus helveticus) were different from those identified in meat-based products (Pediococcus pentosaceus, Weissella cibaria, and Lactococcus lactis). The total bacterial population was approximately 109−10 copies/g regardless of the food item, with the proportion of Lactobacillus spp. determined to be from 78% (dua cai) to 94% (nem chua).

Highlights

Most East Asian fermented foods are non-dairy products including various raw materials such as cereals, soybeans, fruits, and vegetables, as well as fish and other marine products
Tran et al demonstrated that, L. plantarum was predominant in nem chua produced in the north and south of Vietnam, P. pentosaceus was mainly isolated in nem chua from the central region [4]
Microbiota analysis combining denaturing gradient gel electrophoresis (DGGE) and real-time polymerase chain reaction (PCR) was performed on vegetable-based and meat-based fermented foods produced in Hue, a city in the central part of Vietnam

Summary

Introduction

Most East Asian fermented foods are non-dairy products including various raw materials such as cereals, soybeans, fruits, and vegetables, as well as fish and other marine products These foods are produced largely in households or on a small scale using local indigenous microbiota; this is different from western countries in which fermented foods are industrially produced on a large scale using selected starter cultures [1,2]. Many vegetables such as cabbage, eggplant, beansprouts, carrots, bamboo shoots, scallions, and cauliflower can be used for fermentation. The fermentation typically lasts for about two or three days at ambient temperature which can vary from 25 °C to 35 °C [3]

Methods

Results

Discussion

Conclusion