Improved screening procedure for biogenic amine production by lactic acid bacteria and Enterobacteria

Abstract

An improved screening procedure was developed for the detection of amino acid decarboxylase-positive microorganisms (especially lactic acid bacteria and Enterobacteria). Monolayer culture and double layer colour development methods for the detection of amino acid decarboxylase-positive lactic acid bacteria and Enterobacteria were established. Biogenic amine-positive bacteria strain was isolated directly from the samples. The applicability and detection level of the designed medium were quantitatively evaluated by the confirmation of the amine-forming capacity using an HPLC procedure, while tyrosine decarboxylase and lysine decarboxylase genes were detected by PCR with specific primers. The screening method showed a good correlation with the chemical analysis and molecular detection. Enterobacter aerogenes, Enterobacter cloacae, Escherichia coli, Enterococcus faecium, and Enterococcus faecalis were obtained from traditional Chinese sausage. The isolation and screening of amino acid decarboxylase-positive lactic acid bacteria and Enterobacteria can be carried out simultaneously by the improved method.

Keywords

• amino acid decarboxylase
• monolayer culture
• double layer colour development