Hurdle technology for fish preservation

Fresh fish is a highly perishable product due to the chemical composition of fish flesh and the high microbial load on fish surface.The natural microflora that is more adopted to low temperatures results also in lower thermal bacterial shock from natural temperature to the preservation temperature range.The development of new fish processing(e.g.high hydrostatic pressure,osmotic dehydration,high-intensity pulsed light)and packaging(e.g.modified atmospheres,active and intelligent packaging)methods or novel combinations of existing technologies is sought by the industry in the pursuit of producing alternative products,achieving shelf life extension,and management and reducing food waste.In 2014,processed fish was among the most active new product categories.The lack of dissemination of validated laboratory results for the seafood industry is one of the major issues preventing the uptake of minimal and nonthermal processing for fresh fish.However,it has been reported that some bacteria become more resistant under stress(e.g.psychrotolerant lactobacilli).At the same time,the application of some processing methods(e.g.thermal processing)may affect significantly the nutritional and sensory profile of the target food product.The application of several“soft hurdles”may reduce the rate of fish deterioration and spoilage caused by microbial growth.The objective of this article is to review the preservative effect of alternative hurdles on fish quality and shelf life,focusing on recent,combined applications.

Integrating omics technologies for improved quality and safety of seafood products

An essential aspect of product quality of aquatic foods is the rapid and accurate identification of bacterial species.From this perspective omics technologies prove to be very useful in the assessment of the quality and safety of seafood products.Such technologies can identify and detect low levels of contamination by pathogenic and spoilage bacteria and can be used to study the effects caused by processing and storage of seafood products.The integration of food processing with the monitoring of the microbial characteristics using conventional microbiological assays,coupled to molecular techniques may establish the baseline for the development of quicker and more sensitive and reliable methods for seafood safety screening.The use of combined omics technologies,including metagenomics,proteomics and metabolomics,coupled to conventional quality indices such as colour,texture and flavour offer a new tool for novel processing optimization to ensure seafood quality.The aim of this brief review is to outline how omics technologies can generate novel tools for integration into seafood processing and quality control.Considering that the main aspect of the review is the improvement of safety and quality of the final product,from production to consumption,emphasis is given to microbial identification and metabolite detection,the evaluation of the allergenic capacity of fish and seafood and optimization of postharvest processing.Deployment of omics for identification of potential microalgal products of relevance to seafood quality and safety is also considered.

Bacterial community in response to packaging conditions in farmed gilthead seabream

The objective of this study was to evaluate the effect of modified atmosphere packaging(MAP)on fish skin,gills and intestines bacterial microbiome.Whole gilthead seabream was packed aerobically or under modified atmospheres(60%CO_(2),30%N_(2),10%O_(2))and stored isothermally at 0℃.Next Generation Sequencing(NGS)analysis was applied for the characterization of fish microbiome on fish skin,gills,and intestines initially(time of packaging,1 day after harvesting)and after 10 days of isothermal storage at 0℃.NGS results indicated statistically significant differences in families’richness and diversity in the tested fish tissues between aerobic and MAP packaging during storage at 0℃.The most persistent bacteria were Proteobacteria for both packaging types.For fish skin microbiota,the initially prevailing families were Comamonadaceae,Enterobacteriaceae and Moraxellaceae while in the intestines Comamonadaceae,Anaplasmataceae,Bacillaceae and Enterobacteriaceae were the dominant bacteria.At the end of storage period,the fish microbiota was dominated by psychotropic and psychrophilic families(Pseudoalteromonadaceae,Psychromonadaceae,and Shewanellaceae),while families such as Comamonadaceae were persistent under MAP conditions.By 8 days of fish storage at 0℃,МАРsamples exhibited higher sensory scorings than the respective aerobically stored fish,indicating better retention of fish freshness and fish quality attributes under MAP.Based on the results of the study,MAP modified significantly the microbiological status and extended the shelf life of fish.NGS was a powerful tool that provided a more complete assessment compared to a culture-based analysis.