Effect of high hydrostatic pressure (HHP) treatments on microbiological shelf-life of chilled Chilean jack mackerel (Trachurus murphyi)

The effect of high hydrostatic pressure (HHP) treatments (450 and 550 MPa for 3 and 4 min at 20 degrees C) on the microbial behaviour and shelf-life extension of Chilean jack mackerel (Trachurus murphyi) during chilled storage at 4 degrees C was studied. Aerobic mesophilic and psychrophilic microorganisms, as well as hydrogen sulphide-producing bacteria (mainly Shewanella putrefaciens) were enumerated immediately after treatment and during subsequent storage at 4 degrees C. Physicochemical parameters such as pH and TMA-N were also recorded. Results showed that HHP treatments were effective in reducing initial microbial counts and delayed microbial growth during refrigerated storage. HHP treatments were also effective in delaying TMA-N production in the fish during storage. As a result, microbiological shelf-life was significantly (p < 0.05) extended from similar to 6 days (control samples) to similar to 29 and similar to 40 days in pressurised samples at 450 MPa/3 min and 550 MPa/4 min, respectively. Industrial relevance: Chilean jack mackerel (T. murphyi) is recognised as a healthy and nutritious food; however, it is underutilised due to its short microbiological shelf-life as a fresh product. The HHP treatment has been an effective method to control spoilage microorganisms in fish products above 200 MPa and could be considered as an alternative to conventional heating treatments in preparing ready-to-eat or semi-prepared dishes with a minimum loss of micronutrients and extended shelf-life. Thus, HHP treatments were effective in improving microbiological shelf-life of Chilean jack mackerel during chilled storage. (C) 2015 Elsevier Ltd. All rights reserved.