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Case Analysis of Contaminated Bottled Natural Mineral Water: Isolation and Phylogenetic Analysis of Contaminant Bacteria

GAO Wen1, HU Xiaomin2, ZHOU Guoping1,*   

  1. 1. School of Biology and Pharmaceutical Engineering, Wuhan Polytechnic University, Wuhan 430023, China;
    2. Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China
  • Online:2016-04-25 Published:2016-04-13

Abstract:

Objective: To figure out the cause of the occurrence of unpleasant odor in one batch of polyethylene terephthalate
(PET) bottled natural mineral water. Methods: Firstly, we counted and isolated strains from the samples by membrane
filtration and culture on plate count agar (PCA). Secondly, the main spoilage bacteria were identified as Pseudomonas spp.
by 16S rRNA analysis. Then gradient PCR was used to optimize the PCR conditions for amplification of rpoB gene. The
PCR amplified rpoB sequence was analyzed. Results: The main pollutant bacteria in this batch of bottled drinking water was
found to belong to a new species of P. extremaustralis, which was firstly isolated from a temporary pond in Antarctica in 2009.
The rpoB sequence analysis showed that P. extremaustralis spp. was responsible for the occurrence of off-flavor in natural mineral
water. When being inoculated back into normal products, it grew well and stink. Conclusion: Some strains of P. extremaustralis
spp. have the capability of passing through double 0.2 μm-pore-size filters, tolerating ultraviolet sterilization, growing in PET
bottled natural mineral water at low temperature and low oxygen content, and giving out an unpleasant odor.

Key words: PET bottled natural mineral water, Pseudomonas extremaustralis, odor, ultraviolet sterilization, two-step tandem filtration through 0.2 μm-pore-size filters

CLC Number: