Abstract:To develop a safe and efficient cold chain preservation technology for Trichiurus lepturus，this study aimed to evaluate the antibacterial activity and preservation effect of postbiotics from Lacticaseibacillus plantarum SC019 prepared by different processes. Postbiotics were prepared via heat-inactivated （HI）and ultrasonic（US） disruption，respectively，with sterile water as the control. The inhibition zone，biofilm inhibition rate，and DNA leakage were determined. Meanwhile，Trichiurus lepturus was stored at 4 ℃ for 12 d，and the total viable count （TVC），total volatile basic nitrogen （TVB-N），whiteness，and sensory score were dynamically monitored.The results showed that the inhibition zones of HI-POST SC019 against E. coli and S. aureus were （16.50±1.06） mm and （15.94±0.38） mm，respectively，with biofilm inhibition rates reaching 82.14% and 80.06%. The DNA leakage of HI-POST SC019 was significantly higher than that of US-POST SC019 （P＜0.05）. Storage experiments indicated that HI-POST SC019 delayed the time when TVB-N exceeded 30 mg/100 g to the 12th day；during the 12-day storage period，TVC remained below 6 lg（CFU/g），and the sensory score was consistently higher than the acceptable threshold. Compared with the control，HI-POST SC019 extended the refrigerated shelf life of Trichiurus lepturus by approximately 4 d. Therefore，the heat inactivation process can significantly enhance the multi-target antibacterial activity of SC019 postbiotics，delay the spoilage process of Trichiurus lepturus，and maintain its color and texture.