FIG 7.

Quantitative analysis of histamine-producing microorganisms and HDC-encoding gene in low- or high-BA soy sauce samples. (A) The absolute abundance of T. halophilus in high- and low-BA soy sauce samples. (B) Relative quantitative analysis of hdcA between the high- and low-BA samples. The relative copy number was normalized to the copy number of the 16S rRNA gene of T. halophilus. (C) The relative expression level of hdcA gene between the high- and low-BA samples. The relative expression levels of hdcA were normalized to the expression level of the 16S rRNA gene of T. halophilus. (**, P < 0.01; determined by t-test). (D) The ratio of histamine-producing to non-histamine-producing strains in high- and low-BA samples.