To clarify the effect of microbes on the formation of amino acids during the ripening of squid shiokara, changes in the viable cell counts in 2.5% and 10% NaCl-BPG medium, 10% NaCl-PDA medium, and 10% NaCl-LBS medium, and amino acid contents etc. during ripening at 20°C were compared to shiokara containing 10% NaCl with and without antibiotics.
Though the viable cell counts in the shiokara without antibiotics markedly increased during the ripening in contrast to those with antibiotics, neither the total nor the individual amounts of amino acids significantly differed between the samples, suggesting that microbes have a slight effect on the formation of amino acids.
The initial bacterial flora of the shiokara without antibiotics were dominated by Staphylococcus, irrespective of the medium used for counting. The dominant flora in the later stage of ripening, however, differed depending on the media: Staphylococcus dominated on the 2.5% NaCl-BPG medium, while Micrococcus dominated and Streptococcus appeared in the deteriorating stage on the 10% NaCl-BPG medium.