Composition and Microbial Flora of “Kusaya” Gravy of Shikinejima and Kozujima Islands

Abstract

The chemical and microbiological analyses of kusaya gravy were carried out on samples obtained from manufactures at Shikinejima (sample L) and Kozujima (sample NB) Islands.
The compositions of the gravy L and NB were as follows, respectively: pH, 7.16 and 7.52; NaCl concentraion, 5.49% and 5.14%; total nitrogen, 440.7 and 430.9mg/100ml; volatile basic nitrogen, 282.2 and 300.9mg/100ml; trimethylamine, 0.39 and 0.40mg-N/100ml; and viable bacterial counts, 1.3×10⁸ and 1.5×10⁸ cells/ml.
The classification of bacteria at the genus level was performed on 26 strains from gravy L and 17 strains from gravy NB. The dominant flora of the gravy L were Corynebacterium (58%) followed by Moraxella and Pseudomonas; while the dominant flora of the gravy NB were Corynebacterium (35%), Pseudomonas (29%) and Spirillum (24%). These Corynebacterium formed very minute colonies on nutrient agar plate containing 2.5% NaCl.
From the above results, the main characteristics of the gravy of Shikinejima and Kozujima Islands were thought to be similar with those of Niijima, Oshima and Miyakejima Islands.