Isolation and identification of specific spoilage organism from Tilapia wastes enzymatic hydrolysates

Specific spoilage organism of Tilapia Wastes enzymatic hydrolysates during chilled storage was studied by PCR- DGGE and PCR- RFLP.Results indicated that Tilapia enzymatic hydrolysates spoilaged about 20 days at 4℃,and the total number of bacteria increased during 0 ~ 12 days( 8.71 × 102~ 8.13 × 107 cfu / g) gradually,became stable during 12~20 days.There were three types of bacteria by PCR- RFLP analysis of 16 S r RNA from 18 strains of bacteria selected randomly. Type one which dominated 61% of the total bacteria was highly similar with Pseudomonas.The maps of PCR- DGGE showed that the bacteria reduced gradually before spoilaged,and there was only one single band of bacteria at last.Sequencing analysis results of DGGE bands showed that there were three types of bacteria Pseudomonas sp.,Aeromonas and Acinetobacter in the Tilapia Wastes enzymatic hydrolysates,Pseudomonas fluorescens was the predominant bacteria when spoilaged,this conclusion was consistent with RFLP.