Comparison of PCR‐DGGE and PCR‐SSCP analysis for bacterial flora of Japanese traditional fermented fish products,aji‐narezushi and iwashi‐nukazuke

BACKGROUND: The bacterial flora of two Japanese traditional fermented fish products, aji‐narezushi (salted and long‐fermented horse mackerel (Trachurus japonicas) with rice) and iwashi‐nukazuke (salted and long‐fermented sardine (Sardinops melanostica) with rice bran), was analysed using non‐culture‐based polymerase chain reaction (PCR) denaturing gradient gel electrophoresis (DGGE) and culture‐based PCR single‐strand conformation polymorphism (SSCP) methods. RESULTS: Viable plate counts in aji‐narezushi and iwashi‐nukazuke were about 6.3–6.6 and 5.7–6.9 log colony‐forming units g^?1 respectively. In the PCR‐DGGE analysis, Lactobacillus acidipiscis was detected as the predominant bacterium in two of three aji‐narezushi samples, while Lactobacillus versmoldensis was predominant in the third sample. By the PCR‐SSCP method, Lb. acidipiscis and Lactobacillus plantarum were isolated as the predominant bacteria, while Lb. versmoldensis was not detected. The predominant bacterium in two of three iwashi‐nukazuke samples was Tetragenococcus muriaticus, while Tetragenococcus halophilus was predominant in the third sample. CONCLUSION: The results suggest that the detection of some predominant lactic acid bacteria species in fermented fish by cultivation methods is difficult. Copyright © 2010 Society of Chemical Industry