Microbiological changes and biodiversity of cultivable indigenous bacteria in Sanbao larger yellow croaker (Pseudosciaena crocea), a Chinese salted and fermented seafood.

Abstract

Sanbao large yellow croaker is a kind of Chinese salted and fermented seafood processed by adding 50% of salt and fermenting at high temperature [around 30°C] over 20 d. To get a comprehensive understanding of cultivable microorganism's diversity present in its fermentation, the chemical and microbial properties of this product, were detected initially, followed by identification of bacteria recovered from different fermentation periods using PCR-RFLP and 16S rRNA gene sequencing analysis. In total, 105 indigenous isolates were recovered with 3 different medium and majority of the isolates picked up from both MRS and MSA medium were finally clustered into the genus of Staphylococcus (S.). Among the 90 Staphylococci, S. xylosus, S. saprophyticus, and S. nepalensis were the most prevailing cultivable species recovered throughout the whole production process (70 isolates, 77.8%), while 5 other species, namely, S. aureus, S. vitulinus, S. sciuri, S. equorum, and S. succinus formed a minor fraction (20 isolates, 22.2%) of the Staphylococcus communities. Lactic acid bacteria, Pseudomonas, Proteus, and Bacillus constituted trivial populations in the initial period of the fermentation and then gave the way to the Staphylococcus immediately. High salt concentration used during the processing is like to have a pronounced influence on the microbial populations involved. Data obtained in this work could be referred in control and optimization of the fermentation process and selecting suitable strains for aquatic product fermentation.