Inactivation of Baroduric Bacteria Isolated by High Hydrostatic Pressure from Pickled Cowpea

Xuemei Li,Dong Zhao,Tiantian Lin,Anjun Chen,Biao Pu

doi:10.5539/jfr.v1n3p101

Abstract

In this study, Pickled Cowpea, a typical lactic acid fermented vegetable in Sichuan, China, was used as samples to study both species and inactivation of baroduric bacteria isolated by HHP treatment under different pressure levels and different pressure holding time. 16S rDNA gene sequence, amplified using genomic DNA of 4 baroduric bacteria from Pickled Cowpea as templates, were sequenced and then were identified based on the sequence similarity and homology analysis, as B. licheniformis, B. subtilis, B. sonorensis and B. pumilus. The pressure resistance of the 4 strains are compared under pressure from 300 to 500 MPa with holding time from 3 to 25 min. B. pumilus which has higher pressure resistance can be selected as indicator bacteria for applying HHP treatment to Pickle production.

Highlights

Fermentation, a centuried food preservation technology, can naturally prolong the shelf life of vegetable and improve its safety, nutrition and sensory quality
In this study, Pickled Cowpea, a typical lactic acid fermented vegetable in Sichuan, China, was used as samples to study both species and inactivation of baroduric bacteria isolated by High hydrostatic pressure (HHP) treatment under different pressure levels and different pressure holding time. 16S rDNA gene sequence, amplified using genomic DNA of 4 baroduric bacteria from Pickled Cowpea as templates, were sequenced and were identified based on the sequence similarity and homology analysis, as B. licheniformis, B. subtilis, B. sonorensis and B. pumilus
Under the condition of 1% agarose gel electrophoresis, their 16S rDNA amplified and purified products were showed in electrophoresis images (Figure 1), which indicated that the specific bands of amplified products were about 1500 bp according to the Marker band

Summary

Introduction

Fermentation, a centuried food preservation technology, can naturally prolong the shelf life of vegetable and improve its safety, nutrition and sensory quality. A traditional fermented food in China as one of the 4 most popular fermented vegetable in Sichuan, is produced by salt hypertonic effect and lactic acid fermentation. Being popular for unique flavor and nutritional value in China, Pickled Cowpea is selected as research material in this study. Lactic acid bacteria, growing during the lactic acid fermentation, can inhibit the growth of other microorganisms. Due to effect of microorganisms and enzymes which including breeding of spoilage bacteria in industrial production, shelf life was greatly shortened while quality was reduced (Song et al, 2004; Cheigh & Park, 1994). New ways of sterilization, which both extend shelf life and maintain the original quality as far as possible, are requested by modern industrial production

Methods

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Discussion

Conclusion