Abstract:
Abstract: The effect of high hydrostatic pressure (290 MPa, 6 min) on microbial ecology changes of Trichiurus lepturus during vacuum-packaged storage (12 d) was studied via 16S rRNA gene sequencing analysis and phenotypic methods. The microbial colonies of aerobic culture and anaerobic culture, which were obtained from 5 microflora's growth stages (including fresh Trichiurus lepturus, fresh Trichiurus lepturus which were stored under 4℃ for 4, 8 and 12 d after high hydrostatic pressure treatment), were isolated and purified by the tryptic soy agar medium and tryptic soy broth medium, repeatedly classified by the traditional phenotypic methods (morphological, physiological and biochemical characteristics of bacteria strains), and then the bacteria DNA of pure culture was extracted and amplified by the polymerase chain reaction (PCR). Finally, 24 bacteria strains of aerobic culture and anaerobic culture in the vacuum-packaged Trichiurus lepturus under the 4℃ cold storage were obtained. The result showed that Pseudomonas brenneri, Pseudomonas fulva and Psychrobacter faecalis which appeared in the initial microflora of fresh Trichiurus lepturus were inactivated and non-existent after the high hydrostatic pressure treatment; 5 bacteria strains (including Shewanella baltica, Pseudomonas lundensis, Stenotrophomonas rhizophila, Staphylococcus epidermidis and Microbacterium oxydans) gradually reduced and disappeared after the high hydrostatic pressure treatment. Three bacteria strains gradually grew with the extension of storage time, which were Microbacterium halimionae, Macrococcus caseolyticus and Rhizobium larrymoorei. In the whole process of storage after the high hydrostatic pressure treatment, 4 bacteria strains (Moraxella osloensis, Kocuria rhizophila, Carnobacterium maltaromaticum and Dermacoccus nishinomiyaensis) always existed, and they were not sensitive to the high hydrostatic pressure treatment. Especially Carnobacterium maltaromaticum, which had a high proportion of total bacteria amount under the conditions of aerobic and anaerobic cultivation, could be considered as a dominate strain during the 4℃ cold storage. At the end of the shelf life of vacuum-packaged Trichiurus lepturus pretreated by high hydrostatic pressure, 5 bacteria strains (Leucobacter aerolatus, Pantoea agglomerans, Yersinia enterocolitica subsp. Palearctica, Chryseobacterium vrystaatense and Brachybacterium rhamnosum) appeared. The colony evolution of Trichiurus lepturus during the cold storage showed that Gram negative bacteria were sensitive to the high hydrostatic pressure treatment, while Gram positive bacteria had a high tolerance to the high hydrostatic pressure treatment. Under the influence of high hydrostatic pressure treatment, the microorganisms which have stronger ability of causing corruption are inhibited, and the microorganisms which have weaker ability of causing corruption become dominant bacteria, which may be one of the factors that the high hydrostatic pressure treatment can effectively extend the shelf life of Trichiurus lepturus.