Document Detail


Evaluation of agar diffusion bioassay for nisin quantification.
MedLine Citation:
PMID:  14963617     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The agar diffusion bioassay is the most widely used method for the quantification of nisin, due to its high sensitivity, simplicity, and cost-effectiveness. This method is based on the measurement of the inhibition zone produced in nisin-sensitive microorganisms. The size of the zone is affected by many factors, such as nisin-sensitive strain, amount of added agar and surfactant, and pre-diffusion step. This research aims to evaluate the effects of nisin-sensitive strains and pre-diffusion on the accuracy and precision of nisin quantification. Three strains of nisin-sensitive microorganisms (Micrococcus luteus, Lactobacillus sakei, Brochothrix thermosphacta) were tested along with three different incubation processes. The best combination was the method using L. sakei as an indicator strain with pre-diffusion at 4 degrees C for 24 h. Compared with M. luteus and B. thermosphacta, L. sakei gave more accurate and reproducible results. Moreover, the pre-diffusion step resulted in larger inhibition zones and more precise results. Finally, the best combination was validated and compared with the method that is usually used and the result showed that the method using L. sakei with pre-diffusion gave more accurate and precise results.
Authors:
T Pongtharangkul; A Demirci
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Publication Detail:
Type:  Evaluation Studies; Journal Article; Research Support, Non-U.S. Gov't     Date:  2004-02-13
Journal Detail:
Title:  Applied microbiology and biotechnology     Volume:  65     ISSN:  0175-7598     ISO Abbreviation:  Appl. Microbiol. Biotechnol.     Publication Date:  2004 Aug 
Date Detail:
Created Date:  2004-08-13     Completed Date:  2004-10-28     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8406612     Medline TA:  Appl Microbiol Biotechnol     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  268-72     Citation Subset:  IM    
Affiliation:
Department of Agricultural and Biological Engineering, The Pennsylvania State University, University Park, PA 16802, USA.
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MeSH Terms
Descriptor/Qualifier:
Agar
Anti-Bacterial Agents / analysis*
Bacteria / drug effects*
Biological Assay / methods*
Diffusion
Lactobacillus / drug effects*
Microbial Sensitivity Tests
Micrococcus luteus / drug effects*
Nisin / analysis*,  pharmacology,  standards
Reproducibility of Results
Sensitivity and Specificity
Species Specificity
Chemical
Reg. No./Substance:
0/Anti-Bacterial Agents; 1414-45-5/Nisin; 9002-18-0/Agar

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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