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ORIGINAL RESEARCH article

Front. Microbiol.
Sec. Food Microbiology
Volume 16 - 2025 | doi: 10.3389/fmicb.2025.1493947
This article is part of the Research Topic Encapsulated Probiotics: Next-Generation Functional Food Production View all articles

A Vacuum Lyophilization and Bacterial Tablet-based Method for Culture Medium Evaluation and Potential Use in Probiotic Products

Provisionally accepted
Wen Cui Wen Cui 1Liang Zhao Liang Zhao 2*Yuwen Shi Yuwen Shi 1*Wei Feng Wei Feng 3*Xiao Chen Xiao Chen 1*Hui Liu Hui Liu 1*
  • 1 Jinan Disease Prevention and Control Center, Jinan, China
  • 2 Jinan Children's Hospital, Jinan, Shandong Province, China
  • 3 Yantai Yuhuangding Hospital, Yantai, Shandong Province, China

The final, formatted version of the article will be published soon.

    The fundamental step in microbiological detection is the preparation of culture medium. The reliability and accuracy of microbiological assay heavily relies on this step. Currently in China, the most recognized standard method for such medium evaluation is ISO 11133-2014. However, this method requires highly complicated biosafety management, detailed standard strains record-keeping and substantial working time. Bacterial tablet is considered to be a novel strategy for bacteria culture medium evaluation. The filter membrane as a carrier ensures uniform cell dispersion, forming a singular colony that can facilitate counting. We examined the viability and storage durability of vacuum freeze-dried bacterial tablets using a filter membrane as a carrier and utilized the results to evaluate culture medium. We found that the recipe GBSS (Glycerinum, Brain Heart Infusion, Sucrose, Sodium Glutamate) showed the highest survival rate for Escherichia coli in vacuum freeze-drying. As a qualified medium, the productivity of target bacterium should be greater than 0.7. A comparison of freeze-dried bacterial tablet method with ISO 11133-2014 quantitative method showed the sensitivity and specificity of this novel method were 94.1% and 88.9% respectively. The results suggested that vacuum freeze-dried bacterial tablet method had high conformity when compared to ISO 11133-2014 quantitative method ( 2 =0.25, p>0.05; Kappa=0.75). Hence, vacuum freeze-drying method is an integral part of preservation of bacterial strains and the preparation of related biological products. In conclusion, we have developed a novel and effective disposable product for estimating efficiency of the culture medium.

    Keywords: Vacuum freeze-drying, culture medium, cryoprotectant, bacterial tablet, probiotic

    Received: 11 Sep 2024; Accepted: 27 Jan 2025.

    Copyright: © 2025 Cui, Zhao, Shi, Feng, Chen and Liu. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence:
    Liang Zhao, Jinan Children's Hospital, Jinan, Shandong Province, China
    Yuwen Shi, Jinan Disease Prevention and Control Center, Jinan, China
    Wei Feng, Yantai Yuhuangding Hospital, Yantai, Shandong Province, China
    Xiao Chen, Jinan Disease Prevention and Control Center, Jinan, China
    Hui Liu, Jinan Disease Prevention and Control Center, Jinan, China

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.