AUTHOR=Wang Xin-Yun , Xie Jing 

TITLE=Comparison of Physicochemical Changes and Water Migration of Acinetobacter johnsonii, Shewanella putrefaciens, and Cocultures From Spoiled Bigeye Tuna (Thunnus obesus) During Cold Storage

JOURNAL=Frontiers in Microbiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.727333

DOI=10.3389/fmicb.2021.727333

ISSN=1664-302X

ABSTRACT=<p>This study investigates the physicochemical changes and water migration of <italic>Acinetobacter johnsonii</italic> (A), <italic>Shewanella putrefaciens</italic> (S), and cocultured <italic>A. johnsonii</italic> and <italic>S. putrefaciens</italic> (AS) inoculated into bigeye tuna during cold storage. The physicochemical indexes [fluorescence ratio (FR), total volatile base nitrogen (TVB-N), thiobarbituric acid (TBA), trimethylamine (TMA), peroxide value (POV), and pH] of bigeye tuna increased cold storage. A significant decrease in trapped water was found in the AS samples, and direct monitoring of the water dynamics was provided by low-field nuclear magnetic resonance. Samples inoculated with <italic>A. johnsonii</italic> and <italic>S. putrefaciens</italic> also induced the degradation of myofibrillar proteins and weakness of some Z-lines and M-lines. Higher values of physicochemical indexes and water dynamics were shown in the coculture of <italic>S. putrefaciens</italic> and <italic>A. johnsonii</italic> than in the other groups. Therefore, this paper reveals that the coculture of <italic>A. johnsonii</italic> and <italic>S. putrefaciens</italic> resulted in a bigeye tuna that was more easily spoiled when compared to the single culture. This study provides insight into the spoilage potential of <italic>A. johnsonii</italic> and <italic>S. putrefaciens</italic> during cold storage, which further assists in the application of appropriate technologies to keep the freshness of aquatic foods.</p>