Microbial shelf-life extension of chilled Coho salmon ( Oncorhynchus kisutch) and abalone ( Haliotis rufescens) by high hydrostatic pressure treatment

Abstract

This study was carried out to evaluate the effect of high hydrostatic pressure (HHP) treatment on microbial behavior and the shelf-life extension of Coho salmon and abalone during chilled storage at 4 °C. For salmon, HHP treatments were applied at 135, 170, and 200 MPa for 30 s, while abalone treatment consisted of 500 MPa for 8 min and 550 MPa for 3 or 5 min. Spoilage bacteria ( Pseudomonas spp. and hydrogen sulfide-producing bacteria, mainly Shewanella putrefaciens), as well as aerobic mesophilic and psycrophilic microorganisms, were enumerated immediately after treatment and throughout subsequent storage at 4 °C. Results have shown that HHP treatment reduced the initial microbial counts of salmon from 3.16 to 2.2 log units, moreover abalone was reduced from 1.3 log to undetectable levels (<10 CFU g −1). HHP-treatment used for salmon were not sufficient to extend their shelf-life. However, the shelf-life of abalone was extended from 30 (control samples) to >65 days irrespective of HHP treatment applied.