Effects of different ozonized slurry-ice treatments and superchilling storage (−1°C) on microbial spoilage of two important pelagic fish species

Abstract

Combining different preservative treatments for improving quality and safety of fishery products increasingly receives global research attention. Consistent with this pursuit, the current research was undertaken to determine the effects of different ozonized slurry-ice treatments and superchilling (−1°C) storage on microbial spoilage of European anchovy (Eugraulis encrasicolus) and sardine (Sardina pilchardus), which are two commercially important pelagic fish species. After the catch (within <5 hr) and at defined scheduled storage times, ozone has been discharged once on sardine (herein referred to as "One-T") and repeatedly/sequentially on European anchovy (herein referred to as "Seq-T"). Microbiological analyses enumerated total viable count (TVC), Bacillus spp., Enterobacteriaceae, Lactobacillus spp., Moraxella spp., Shewanella spp., Listeria monocytogenes and Pseudomonas spp. Independent of potential antimicrobial effects of ozone during superchilling storage, no Listeria spp., Shewanella spp., Moraxella spp., and Bacillus spp. were found in all processed samples. While Enterobacteriaceae and Lactobacillus spp. were detected at below 1 log cfu/g, both TVC and Pseudomonas spp. proliferated at different rates throughout superchilling storage. The repeated ozone-treated ("Seq-T") showed lower TVC and Pseudomonas spp. values compared with one-time treated ("One-T") slurry-iced and control samples. Thus, combined slurry-ice and superchilling storage at Seq-T produced improved antimicrobial activity over One-T application. Largely, ozonized slurry-ice outcomes/results appear promising thanks to superchilling storage.

Slurry-iced superchilling storage of current study is contextualized with those of ice-stored/refrigerated storage situations previously reported. We do this by schematic illustration of estimated proliferation increment(s)/trend(s) of some (relevant/specific) bacterial species detected in (some) small pelagic fishery products as affected by different storage temperatures and times (days). Trends A–E shows the different proliferation patterns of bacterial species such as Enterobacteriaceae, Lactobacillus, Pseudomonas spp., Shewanella as it proliferates at different rates under varying cold storage temperature conditions.

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