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.

Slurry ice as an alternative cooling medium for fish harvesting and transportation:Study of the effect on seabass flesh quality and shelf life

The objective of the study was to investigate the efficiency of slurry ice during harvesting and transportation of European sea bass(Dicentrarchus labrax)to retain flesh quality and extend shelf life,compared with conventional flake ice.Fish was slaughtered and transported in different mixtures of slurry ice and conventional flake ice(C:slaughtered and transported in 100%flake ice-Control samples,SC:slaughtered in 100%slurry ice and transported in 100%flake ice,S50:slaughtered and transported in 50%slurry ice-50%flake ice,S100:slaughtered and transported in 100%slurry ice)and subsequently stored under controlled isothermal conditions at 0℃for shelf life modelling and flesh quality evaluation(proteolytic enzymes).The replacement of conventional flake ice with slurry ice as a slaughtering method led to improved quality stability during subsequent refrigerated storage and shelf life extension,in terms of microbial growth,flesh quality and sensory degradation of fish.Based on microbial growth,the shelf life of C samples was found to be 19 days,whereas the shelf life of S50/S100 and SC was 21 and 25 days,respectively,showing that the replacement of flake ice with slurry ice resulted in 2–6 days shelf life extension of whole sea bass stored at 0℃.The use of slurry ice at slaughter and flake ice in transportation was accompanied by low activities and late peaks of all four enzymes that is expected to lead to delayed proteolytic degradation and extended freshness.

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.