Isolation,identification and spoilage ability analysis on the particular spoilage bacteria of penaeus vannamei in the ice temperature storage

In order to isolate and identify penaeus vannamei,s spoilage bacteria and measure their spoilage ability in ice temperature storage conditions,the freezing point of penaeus vannamei was determined based on freezing experiment and the spoilage bacteria were separated from penaeus vannamei which was stored under the temperature between 0 ℃ and the freezing point,the isolated microbes were identified by morphological observation and molecular biology methods.The separated spoilage bacteria were inoculated into sterilized shrimp juice,hydrogen sulfide,degradated proteins and volatile base nitrogen( TVB- N) were selected to evaluate the spoilage ability.The results showed that 12 strains of spoilage bacteria were isolated from penaeus vannamei,they were Shewanella hafniensis,Acinetobacter johnsonii,Planoccoccus citreus,Bacillus cereus,Acinetobacter beijerinckii,Enterobacter hormaechei,Arthrobacter bergeri,Bacillus licheniformis,of which X1 and X10 may be a potential new species or genus. In ice temperature storage conditions,dominant spoilage bacteria leading to the corruption of penaeus vannamei were Shewanella hafniensis,X1,Acinetobacter johnsonii and Acinetobacter beijerinckii.