Evaluation of an ozone–slurry ice combined refrigeration system for the storage of farmed turbot (Psetta maxima)

Slightly acidic electrolyzed water-slurry ice: shelf-life extension and quality maintenance of mackerel (Pneumatophorus japonicus) during chilled storage

BACKGROUND

Different ice treatments were applied for the preservation of mackerel (Pneumatophorus japonicus). The quality changes of samples treated with flake ice (Control), slurry ice (SI) and slightly acidic electrolyzed water-slurry ice (SAEW-SI) in microbiological, physicochemical, protein characteristic, and sensory evaluation were investigated during chilled storage.

RESULTS

SAEW-SI showed a significant advantage for the inhibition of microbial growth, which could extend the shelf-life for another 144 h at least, compared with Control group. SAEW-SI treatment also showed a strong inhibition for the increase in pH, total volatile basic nitrogen (TVB-N), K-value, histamine and metmyoglobin (MetMb) content. Results of texture profile analysis (TPA) and water holding capacity (WHC) indicated that SAEW-SI can obviously suppress the decrease of hardness value, and have a better protective effect on muscle structure compared to flake ice and SI (P < 0.05). During the whole experiment, the highest sensory scores and a* were obtained in the SAEW-SI group, which indicated that SAEW-SI treatment could maintain better sensory characteristics. According to the results of thiobarbituric acid reactive substances (TBARS) and fluorescence spectroscopy analysis, SAEW-SI treatment could effectively retard protein degradation and lipid oxidation compared with Control and SI group. In maintaining the quality of mackerel, SAEW-SI shows a better effect than SI due to the synergistic effect of fence factors.

CONCLUSION

The results demonstrated that the shelf-life of mackerel could be extended and the quality of mackerel could be maintained effectively with SAEW-SI treatment during chilled storage. © 2022 Society of Chemical Industry.

A Novel Strategy for Accelerating Pumpable Ice Slurry Production with Ozone Micro-Nano Bubbles and Extending the Shelf Life of Larimichthys polyactis

In this study, a novel strategy for accelerating the production of pumpable ice slurry (PIS) by using ozone micro-nano bubbles (O₃-MNBs) was proposed. The effect of PIS containing sodium alginate (SA) and O₃-MNBs on the preservation of small yellow croaker (Larimichthys polyactis) was investigated. The results indicate that using SA solution containing O₃-MNBs instead of only SA solution resulted in quicker production of PIS by promoting ice nucleation and eliminating supercooling. The distribution and positive effect of O₃-MNBs as a nucleation agent on freezing characteristics were discussed. Microbial concentrations, pH, total volatile basic nitrogen, and thiobarbituric acid reactive substance content were also examined. Storage in novel PIS (containing O₃-MNBs) had higher performance than storage in flake ice or conventional PIS due to the strong bacteriostatic ability of O₃. Therefore, O₃-MNBs injection can be used as a novel method for PIS production and the preservation of fresh marine products.

Improvements in chitosan-based slurry ice production and its application in precooling and storage of Pampus argenteus

The effects of microbubbles in chitosan-based slurry ice production were investigated, and the efficiency of chitosan-based slurry ice was evaluated for silver pomfret (Pampus argenteus) precooling and storage at 0 °C. Microbubbles generated though agitation accelerated slurry ice production by promoting ice nucleation and eliminating supercooling. Higher bubble counts improved freezing, but overly large bubbles reduced the performance. The rheological properties of chitosan solutions were also investigaed, and solutions with higher viscosity formed more bubbles. Experiments investigating precooling rates, microbial concentrations, pH, thiobarbituric-acid-reactive substances, and total volatile basic nitrogen all confirmed that chitosan-based slurry ice had higher performance than flake ice or conventional slurry ice. Chitosan-based slurry ice can be used for precooling in the fish industry to reduce energy consumption, accelerate precooling, reduce microbial growth, and improve shelf life.

Analysis of Alternative Shelf Life-Extending Protocols and Their Effect on the Preservation of Seafood Products

Seafood is essential to a healthy and varied diet due to its highly nutritious characteristics. However, seafood products are highly perishable, which results in financial losses and quality concerns for consumers and the industry. Due to changes in consumer concerns, demand for healthy products has increased. New trends focusing on reducing synthetic preservatives require innovation and the application of additional or alternative strategies to extend the shelf life of this type of product. Currently, refrigeration and freezing storage are the most common methods for fish preservation. However, refrigeration alone cannot provide long shelf-life periods for fish, and freezing worsens sensorial characteristics and consumer interest. Therefore, the need to preserve seafood for long periods without exposing it to freezing temperatures exists. This review focuses on the application of other approaches to seafood products, such as biodegradable films and coating technology; superchilling; irradiation; high-pressure processing; hyperbaric storage; and biopreservation with lactic acid bacteria, bacteriocins, or bacteriophages. The efficiency of these techniques is discussed based on their impact on microbiological quality, sensorial degradation, and overall preservation of the product’s nutritional properties. Although these techniques are already known, their use in the industrial processing of seafood is not widespread. Thus, the novelty of this review is the aggregation of recent studies on shelf life extension approaches, which provide useful information for the selection of the most appropriate technology and procedures and industrial innovation. Despite the fact that all techniques inhibit or delay bacterial proliferation and product decay, an undesirable sensory impact may occur depending on the treatment conditions. Although no technique appears to replace refrigeration, the implementation of additional treatments in the seafood processing operation could reduce the need for freezing, extending the shelf life of fresh unfrozen products.

Seasonal Pattern of the Effect of Slurry Ice during Catching and Transportation on Quality and Shelf Life of Gilthead Sea Bream

The objective of the present study was the evaluation of the effect of slurry ice, as an alternative cooling medium during harvesting and transportation, on the quality parameters (e.g., microbiological stability, sensory attributes, physicochemical changes) and shelf life of fish. The effect of seasonal variability of seawater temperature on fish preservation using the tested cooling media was also investigated. Gilthead sea bream (Sparus aurata) was slaughtered and transported in different mixtures of conventional flake ice and slurry ice for 24 h. Three mixtures of ice were tested as T: slaughtered in flake ice and transported in flake ice (control), TC: slaughtered in slurry ice and transported in flake ice, T50: slaughtered and transported in slurry ice 50%–flake ice 50%. Samples were subsequently stored isothermally at 0 °C for shelf-life evaluation. Three independent experiments were performed at three different periods, i.e., January, April, and September, referring to a sea water temperature range of 13.3–26.8 °C. Higher sea water temperatures at catching led to lower microbial growth rates and proteolytic enzyme activities and longer shelf life of refrigerated whole fish. The partial replacement of conventional flake ice with slurry ice improved the quality and extended the shelf life of fish at 0 °C by 2–7 days. The results of the study support that the use of slurry ice may enable better quality maintenance and significant shelf-life extension of whole gilthead sea bream.

Chemical-Based Methodologies to Extend the Shelf Life of Fresh Fish-A Review

Due to its characteristics, fresh fish is a highly perishable food with a very short shelf-life under refrigeration. Several methods have been introduced to slow down its deterioration, such as by means of oxygen depletion of the food package (vacuum packaging), or by changing the natural atmosphere that is in contact with the fresh fish (modified atmosphere packaging), or by the use of chemicals generally recognized as safe: such compounds can be directly applied (by dipping or spraying) or incorporated into packaging materials and slowly migrate to the product, exerting a hurdle effect against microbial development and lipid oxidation (active packaging). This review aims to cover the most recent advances in chemical-based approaches for fresh fish preservation, applied either singly or in combination. Vacuum packaging, modified atmosphere, and active packaging preservation methodologies are presented, along with the inclusion of chemical additives, such as organic acids and natural extracts, and their combination with icing systems. Advantages and disadvantages of these methodologies and their impact on fresh fish quality and shelf-life are discussed, reaching the conclusion that both are positively influenced overall. Indeed, the contribution of chemical-based strategies for fresh fish preservation is undeniable, and is expected to be a research topic of increasing interest in the future.

Application of the curcumin-mediated photodynamic inactivation for preserving the storage quality of salmon contaminated with L. monocytogenes

The effect of curcumin-mediated blue light-emitting diode (LED) photodynamic inactivation (PDI) for preserving the quality of salmon contaminated with Listeria monocytogenes was investigated by microbiological, physical, chemical and histological methods during sample storage at 4 ℃ and 25 ℃. The results showed that PDI decelerated the proliferation of L. monocytogenes on salmon during storage at 25 ℃, with the maximum inhibition reaching 4.0 log₁₀ CFU/g (99.99%), compared to the negative control. Moreover, PDI greatly retarded the increase in pH (P < 0.05) and the production of TVB-N, retarded the accumulation of free fatty acids, and decelerated the degradation of proteins, ultimately preserving the high nutritional value of the salmon. In addition, PDI effectively prevented a change in colour and retarded the loss of water from the salmon, thereby conserving its texture and sensory properties. Therefore, PDI is a promising and valid non-thermal technology to use for fish preservation.

Innovative Seafood Preservation Technologies: Recent Developments

Fish and fishery products are among the food commodities of high commercial value, high-quality protein content, vitamins, minerals and unsaturated fatty acids, which are beneficial to health. However, seafood products are highly perishable and thus require proper processing to maintain their quality and safety. On the other hand, consumers, nowadays, demand fresh or fresh-like, minimally processed fishery products that do not alter their natural quality attributes. The present article reviews the results of studies published over the last 15 years in the literature on: (i) the main spoilage mechanisms of seafood including contamination with pathogens and (ii) innovative processing technologies applied for the preservation and shelf life extension of seafood products. These primarily include: high hydrostatic pressure, natural preservatives, ozonation, irradiation, pulse light technology and retort pouch processing.

Principles and recent applications of novel non-thermal processing technologies for the fish industry-a review

Thermal treatment is a traditional method for food processing, which can kill microorganisms but also lead to physicochemical and sensory quality damage, especially to temperature-sensitive foods. Nowadays consumers' increasing interest in microbial safety products with premium appearance, flavor, great nutritional value and extended shelf-life has promoted the development of emerging non-thermal food processing technologies as alternative or substitution to traditional thermal methods. Fish is an important and world-favored food but has a short shelf-life due to its extremely perishable characteristic, and the microbial spoilage and oxidative process happen rapidly just from the moment of capture, making it dependent heavily on post-harvest preservation. The applications of novel non-thermal food processing technologies, including high pressure processing (HPP), ultrasound (US), pulsed electric fields (PEF), pulsed light (PL), cold plasma (CP) and ozone can extend the shelf-life by microbial inactivation and also keep good sensory quality attributes of fish, which is of high interest for the fish industry. This review presents the principles, developments of emerging non-thermal food processing technologies, and also their applications in fish industry, with the main focus on microbial inactivation and sensory quality. The promising results showed great potential to keep microbial safety while maintaining organoleptic attributes of fish products. What's more, the strengths and weaknesses of these technologies are also discussed. The combination of different food processing technologies or with advanced packaging methods can improve antimicrobial efficacy while not significantly affect other quality properties under optimized treatment.

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

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.

Valorization of Proteins from Co- and By-Products from the Fish and Meat Industry

Large volumes of protein-rich residual raw materials, such as heads, bones, carcasses, blood, skin, viscera, hooves and feathers, are created as a result of processing of animals from fisheries, aquaculture, livestock and poultry sectors. These residuals contain proteins and other essential nutrients with potentially bioactive properties, eligible for recycling and upgrading for higher-value products, e.g. for human, pet food and feed purposes. Here, we aim to cover all the important aspects of achieving optimal utilization of proteins in such residual raw materials, identifying those eligible for human consumption as co-products and for feed applications as by-products. Strict legislation regulates the utilization of various animal-based co- and by-products, representing a major hurdle if not addressed properly. Thorough understanding and optimization of all parts of the production chain, including conservation and processing, are important prerequisites for successful upgrading and industrial implementation of such products. This review includes industrially applied technologies such as freezing/cooling, acid preservation, salting, rendering and protein hydrolysis. In this regard, it is important to achieve stable production and quality through all the steps in the manufacturing chain, preferably supported by at- or online quality control points in the actual processing step. If aiming for the human market, knowledge of consumer trends and awareness are important for production and successful introduction of new products and ingredients.

Use of acidic electrolyzed water ice for preserving the quality of shrimp

Electrolyzed water ice is a relatively new concept developed in food industry in recent years. The effect of acidic electrolyzed water (AEW) ice on preserving the quality of shrimp (Litopenaeus vannamei) was investigated. Physical, chemical, and microbiological changes of the shrimp were examined during the storage. The results showed that compared with tap water (TW) ice, AEW ice displayed a potential ability in limiting the pH changes of shrimp flesh and significantly (p < 0.05) retarded the changes of color difference and the formation of total volatile basic nitrogen (TVBN). And AEW ice treatment had no adverse effects on the firmness of shrimp. Conventional plate count enumeration and PCR-DGGE demonstrated that AEW ice had a capability of inhibiting growth of bacteria on raw shrimp, and the maximum reductions of population reached >1.0 log CFU/g (>90%) on the sixth day. Moreover, AEW ice was clearly more efficient in maintaining the initial attachments between muscle fibers in shrimp according to histological section analysis. On the basis of above analysis, AEW ice can be a new alternative of traditional sanitizer to better preserve the quality of seafood in the future.

Decontamination of Raw Foods Using Ozone-Based Sanitization Techniques

Popular foods such as fresh produce and dry nuts are increasingly implicated in outbreaks of food-transmitted diseases. These products are not amenable to conventional processing technologies; therefore, many alternative decontamination methods are actively investigated. Ozone is a versatile sanitizer with promising applications in some high-risk foods. This antimicrobial agent is active against a broad spectrum of microorganisms, and it can be used effectively in its gaseous or aqueous state. The flexibility afforded by ozone use makes it a viable option for application on easy-to-damage products like fresh produce. If process parameters are adequately controlled, ozone treatment can enhance safety and increase shelf life without adversely affecting product quality. Despite these advantages, ozone may not be suitable for some applications, including treatment of liquid foods and products rich in unsaturated fats and soluble proteins. Ozone, as a powerful oxidizer, must be carefully controlled at all times, and equipment must be rigorously maintained to ensure safety of workers.

Use of electrolyzed water ice for preserving freshness of pacific saury (Cololabis saira)

The effects of electrolyzed water ice (EW-ice), compared with traditional tap water ice (TW-ice), on the microbiological, chemical, and sensory quality of Pacific saury (Cololabis saira) stored for a period of up to 30 days at 4 degrees C were evaluated. EW-ice with active chlorine at a concentration of 34 mg/kg was prepared from weak acidic electrolyzed water, whose pH, oxidation-reduction potential, and chlorine content were 5, 866 mV, and 47 mg/liter, respectively. Microbiological analysis showed that EW-ice, compared with TW-ice, markedly inhibited the growth of both aerobic and psychrotrophic bacteria in saury flesh during refrigerated storage, primarily because of the action of active chlorine. Chemical analysis revealed that EW-ice retarded the formation of volatile basic nitrogen and thiobarbituric acid-reactive substances and reduced the accumulation of alkaline compounds in the fish flesh in comparison with TW-ice. Sensory analysis confirmed that the freshness of saury was better preserved in EW-ice than in TW-ice and showed that the saury stored in EW-ice had a shelf life that was about 4 to 5 days longer than the fish stored in TW-ice.