Development of shelf-stable, ready-to-eat (RTE) shrimps (Penaeus indicus) using -radiation as one of the hurdles

Inhibitory effects of pH, salinity, and tea polyphenols concentration on the specific spoilage organisms isolated from lightly‐salted large yellow croaker ( Pseudosciaena crocea )

Proteus vulgaris and Hafnia alvei were identified as specific spoilage organisms (SSOs) isolated from the refrigerated lightly‐salted large yellow croaker (Pseudosciaena crocea). In this work, the inhibitory effects of pH, salinity, and tea polyphenols concentration on both strains were investigated. Modified Gompertz models were used to estimate the kinetic parameters μ_m (maximum specific growth rate) and λ (duration of lag phase) of the two strains under different conditions, demonstrating that their growth rates decreased with the decrease of pH as well as the increase of salinity and tea polyphenols concentration, and the growths of both strains stopped while the salinity and tea polyphenols concentration increased to 0.05 and 5%, respectively. Response surface methodology (RSM) based on a three‐level three‐factor Box–Behnken Design (BBD) was employed to optimize the combination of these three antibacterial factors. The results showed that the optimum inhibitory conditions were: tea polyphenols concentration 0.05%, salinity 3.46%, and pH 6.96 to inhibit the growth of P. vulgaris; tea polyphenols concentration 0.05%, salinity 3.45%, and pH 6.94 to inhibit H. alvei. Validation experiments were performed and demonstrated that under these conditions, the growth of the two SSOs could be 100% inhibited. This research provided references for the inhibition of the SSOs of lightly‐salted large yellow croaker and the extension of its shelf life.

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.

Synergistic Effects of Combined Chlorine and Vitamin B1 on the Reduction of Murine Norovirus-1 on the Oyster (Crassostrea gigas) Surface

This study investigated the synergistic effects of combined chlorine (200, 500, 700, and 1000 ppm) and vitamin B₁ (1000, 2000, and 3000 ppm) on the murine norovirus-1 (MNV-1), a human norovirus (NoV) surrogate, on oyster surface. Vitamin B₁ slightly reduced MNV-1 (0.04-0.3 log-reduction), whereas chlorine significantly reduced MNV-1 (0.4-1.0 log-reduction). The combined chlorine and vitamin B₁ resulted in a 0.52-1.97 log-reduction of MNV-1. The synergistic reduction in the MNV titer was not dependent on the concentrations of chlorine and vitamin B₁, and it ranged between 0.08 and 1.03 log₁₀ PFU/mL. The largest synergistic reduction observed was for the combined 700 ppm chlorine and 1000 ppm vitamin B₁. The pH and mechanical texture of the oysters were not significantly changed by the combined 0-1000 ppm chlorine and 3000 ppm vitamin B₁. The overall sensory acceptability were significantly (P < 0.05) reduced in oysters treated with 1000 ppm chlorine and 3000 ppm vitamin B₁ than in those treated with 0-700 ppm chlorine and 3000 ppm vitamin B₁. This study suggests that the combined 700 ppm chlorine and 3000 ppm vitamin B₁ could potentially be used to reduce NoV on oyster surface without causing concomitant changes in the mechanical texture, pH, or sensory qualities of the oysters.

Innovative technologies for producing and preserving intermediate moisture foods: A review

Intermediate moisture foods (IMF) or semi-dried foods (SDF) have gained more attention worldwide having features very similar to fresh food products, but with a longer shelf life. This review presents the recent developments in novel technologies and methods for the production and preservation of IMF. These include new drying methods, using agents to reduce water-activity, innovative osmotic dehydration technologies, electro-osmotic dewatering, thermal pasteurization, plasma treatments (PT), high pressure processing (HPP), modified atmosphere packaging (MAP), edible coating, active packaging (and energy efficiency, improve quality and extend the shelf life of the final food AP) and hurdle technologies (HT). Innovative methods applied to producing and preserving IMF can enhance both drying products. Yet more systematic research is still needed to bridge knowledge gaps, in particular on inactivation kinetics and mechanisms related to thermal and non-thermal pasteurization technologies for control of pathogens and spoilage micro-organisms in IMF.

Synergistic Effects of Electron-beam Irradiation and Leek Extract on the Quality of Pork Jerky during Ambient Storage

To investigate the synergistic effect(s) of electron-beam (EB) irradiation and leek (Allium tuberosum Rottler) extract on the quality of pork jerky during ambient storage, we irradiated prepared pork jerky samples (control and samples with 0.5% and 1.0% leek extract) with EB technology at doses of 0, 1, 2, and 4 kGy, stored them for 2 months at 25°C, and analyzed them. Water activity was 0.73 to 0.77 in non-irradiated samples, and no significant difference in the water activity was observed between the samples treated with leek and the control. The total aerobic bacterial count was significantly decreased with an increase in the irradiation dose and leek extract addition when compared to that of the control (4.54±0.05 log CFU/g). Further, the Hunter color values (L*, a*, and b*) were found to be significantly decreased following leek extract addition and EB irradiation. However, the color values, especially the a* value of the irradiated samples significantly increased during storage. Notably, increasing the EB irradiation dose enhanced the peroxide value. Sensory evaluation revealed that irradiation decreased flavor and overall acceptability. Our findings suggest the use of EB irradiation in combination with leek extract to improve the microbiological safety of pork jerky. However, in order to meet market requirements, novel methods to enhance the sensory quality of pork jerky are warranted.

Effects of antimicrobial coatings and cryogenic freezing on survival and growth of Listeria innocua on frozen ready-to-eat shrimp during thawing

Foodborne pathogens such as Listeria monocytogenes could pose a health risk on frozen ready-to-eat (RTE) shrimp as the pathogen could grow following thawing. In this study, antimicrobial-coating treatments alone, or in combination with cryogenic freezing, were evaluated for their ability to inhibit the growth of Listeria innocua, a surrogate for L. monocytogenes, on RTE shrimp. Cooked RTE shrimp were inoculated with L. innocua at 3 population levels and treated with coating solutions consisting of chitosan, allyl isothiocyanate (AIT), or lauric arginate ester (LAE). The treated shrimp were then stored at -18 °C for 6 d before being thawed at 4, 10, or 22 °C for either 24 or 48 h. Results revealed that antimicrobial coatings achieved approximately 5.5 to 1 log CFU/g reduction of L. innocua on RTE shrimp after the treatments, depending on the inoculated population levels. The coating-treated shrimp samples had significantly (P < 0.05) less L. innocua than controls at each thawing temperature and time. Cryogenic freezing in combination with coating treatments did not achieve synergistic effects against L. innocua. Antimicrobial coatings can help to improve product safety by reducing Listeria on RTE shrimp.

Development of shelf-stable, ready-to-eat (RTE) shrimps ( Litopenaeus vannamei ) using water activity lowering agent by response surface methodology

Three water-activity-lowering agents (composite phosphate, sorbitol and glycerol) were used to develop a kind of shelf-stable, ready-to-eat (RTE) shrimp. Formula of water-activity- lowering agents was optimized by response surface methodology (RSM) using a central composite design. Model equation was proposed with regard to the contents of composite phosphate (X1), sorbitol (X 2) and glycerol (X3) : [Formula: see text]. The model with a very low probability value (P < 0.0003) was highly significant and the value of lack-of-fit was 0.4028, indicating that the model could predict water activity of shrimps using different agents. Composite phosphate of 0.22%, sorbitol of 3.12% and glycerol of 2.51% were found to be the optimal condition to obtain the lowest water activity of 0.884. Compared to the control shrimps, RTE shrimps treated with water-activity-lowering agents had a longer shelflife and higher sensorial acceptability. During storage at temperature of 35 °C, the quality of RTE shrimps in term of appearance, flavor and texture was found to be superior to the untreated ones. Texture profile, TBARS value, contents of astaxanthin and free amino acid of treated samples were found to be decreased slower from origin value compared to that of untreated samples. These RTE shrimps were biologically safe and sensorially acceptable after 30 days of storage at temperature of 35 °C. Briefly, the application of water-activity-lowering agents extent the shelflife of RTE shrimps obviously and would be beneficial for the exploitation of white shrimp.

Impact of irradiation on fish and seafood shelf life: a comprehensive review of applications and irradiation detection

Irradiation is one of the most important and effective methods towards food preservation despite the consumer lack of trust and aversion towards this method. Irradiation effectiveness greatly depends on the dose provided to food. This review aims at summarizing all available information regarding the impact of irradiation dose on the shelf life and microflora and sensory and physical properties of fish, shellfish, molluscs, and crustaceans. The synergistic effect of irradiation in conjunction with other techniques such as salting, smoking, freezing, and vacuum packaging was also reported. Another issue covered within the frame of this review is the detection (comparison of methods in terms of their effectiveness and validity) of irradiated fish and seafood. The information related to fish and seafood irradiation and its detection is presented by means of 11 comprehensive tables and 9 figures.

Microbial population, physicochemical quality, and allergenicity of molluscs and shrimp treated with cobalt-60 gamma radiation

Frozen molluscs (squid, octopuses, and cuttlefish) and crustaceans (shrimp) were irradiated using a cobalt-60 gamma source, at different doses, in order to investigate the effects of gamma radiation on their microbial population, organoleptic characteristics, lipid profile, and tropomyosin content. Irradiation of shrimp and squid with either 2.5 or 4.7 kGy reduced mesophilic bacteria contamination to low or nondetectable levels, respectively, whereas irradiation of octopus and cuttlefish with the same doses reduced the bacterial population. Irradiation treatment had no significant (P > 0.05) effect on the total lipid content and the major detected classes of polar and neutral lipids, whereas it significantly (P < 0.05) increased the contents of neutral lipids in octopus mantle and in shrimp muscle and cephalothorax samples. The total fatty acid content and the omega-3: omega-6 fatty acid ration was not affected. A dose-dependent significant (P < 0.05) decrease in the ratio of polyunsaturated fatty acids:saturated fatty acids was observed. With the increase in radiation dose, redness (a) and yellowness (b) values showed a variation, whereas the lightness (L) value was significantly (P < 0.05) decreased in mollusc mantles and shrimp muscle and increased in shrimp cephalothorax. The total of color changes ( delta E) increased (P < 0.05) as the dose increased. Significant (P < 0.05) changes in textural properties were observed with radiation treatment in octopus tentacles and in squid and cuttlefish mantle. The amount of tropomyosin, which is the major mollusc and crustacean allergen in the irradiated organisms, was reduced by gamma radiation, depending on the dose.