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Improved screening procedure for biogenic amine production by lactic acid bacteria
1Department of Nutrition and Food Science-CeRTA, Faculty of Pharmacy, University of Barcelona, Spain. bover@farmacia.far.ub.es
International Journal of Food Microbiology
|December 22, 1999
Summary
A new screening plate method effectively detects amino acid decarboxylase-positive microorganisms, particularly lactic acid bacteria (LAB), and their biogenic amine production. This simple, sensitive method correlates well with chemical analysis for identifying amine-forming LAB.
Area of Science:
- Food Microbiology
- Analytical Chemistry
- Biotechnology
Background:
- Biogenic amines (BA) are produced by microorganisms and can impact food safety and quality.
- Lactic acid bacteria (LAB) are significant producers of BA, necessitating reliable detection methods.
- Existing methods for detecting BA production by microorganisms can be complex or lack sensitivity.
Purpose of the Study:
- To develop and validate an improved screening plate method for detecting amino acid decarboxylase-positive microorganisms, focusing on LAB.
- To quantitatively evaluate the suitability and detection limits of the new medium using HPLC analysis.
- To investigate the BA-producing potential of various LAB and Enterobacteriaceae strains.
Main Methods:
- Development of a modified screening medium with adjusted glucose, NaCl, buffer (calcium carbonate, potassium phosphate), and pyridoxal-5-phosphate.
- Quantitative evaluation of amine-forming capacity using High-Performance Liquid Chromatography (HPLC).
- Testing a diverse collection of LAB (starter, protective, type strains, food isolates) and Enterobacteriaceae strains.
Main Results:
- The improved screening plate method demonstrated good correlation with HPLC chemical analysis.
- Tyramine was the predominant BA produced by the investigated LAB strains.
- Enterococci, carnobacteria, and specific Lactobacillus strains (Lb. curvatus, Lb. brevis, Lb. buchneri) were major tyramine producers; Enterobacteriaceae produced cadaverine and putrescine. Histamine production was negligible.
Conclusions:
- The developed screening plate method is a simple, sensitive, and suitable tool for investigating BA production capacity in LAB.
- The method aids in identifying specific LAB groups and strains with high tyramine-forming potential.
- Understanding BA production profiles of microorganisms is crucial for food safety and quality control.