The Effects of Cold Plasma Application on Quality and Chemical Spoilage of Pacific White Shrimp (Litopenaeus vannamei) during Refrigerated Storage

Pacific white shrimp (Litopenaeus vannamei) is an important species in aquaculture worldwide. Post-mortem changes during cold storage reduce the quality of shrimp and shorten its shelf life. Cold plasma (CP) was applied for 45, 90, and 150s as T₁, T₂, and T₃, respectively, to fresh harvested shrimp. The biochemical parameters and melanosis were analyzed in comparison to metabisulphite treated (T_M) and control during 12 days of refrigerated storage. The results highlighted lower rate of increase in pH, total volatile base nitrogen (TVB-N) content, thiobarbituric acid reactive substances (TBARS), free fatty acid (FFA), peroxide value (PV), and fluorescent compounds (FC) in shrimp exposed to CP and metabisulphite compared to control (P < 0.05). Although CP lowered biochemical changes in T₁ and T₃ shrimp, T₂ was the most effective treatment in reducing undesirable changes and improving quality of shrimp. In all storage periods, melanosis was significantly lower in T₂, T₃, and T_M samples. Results demonstrate that CP exposure effectively decreases relative activity of polyphenol oxidase (PPO) enzyme, and prolonging the exposure to CP for 150 s resulted in 50% reduction in enzyme activity. We conclude that application of CP for 90 s was the most efficient circumstance to extend shelf life of white shrimp during cold storage.     

Synergic Effects of Light Salting,Vacuum Packaging,and Onion Extract on the Quality Retention of Refrigerated Rainbow Trout (Oncorhynchus mykiss) Fillets

This experiment investigated the synergistic effects of vacuum packaging, light salting, and onion extract on the shelf life of rainbow trout (Oncorhynchus mykiss) fillets stored under refrigeration. The chemical, microbial, and organoleptic changes were monitored for up to 18 days in fillets. Total volatile basic nitrogen (TVB-N) and free fatty acid (FFA) values were evident in the order: control (without salting, vacuum packaging, and extract) > air packaged, salted (APS) > vacuum packaged, salted (VPS) > and vacuum packaged, salted, containing 2% and 4% (v/w) onion extract (2% and 4% VPSOE) throughout the storage period. Thiobarbituric acid values in APS groups were higher than control groups. Data from microbial assay showed that treatment with 2% and 4% VPSOE decreased total viable microbial count (TVC) compared with other treatments. APS, VPS, and VPSOE samples remained acceptable for up to 8, 12, and 15 days, respectively. The most suitable indices for determining shelf life of rainbow trout fillets are TVC.     

Quality preservation of salted,vacuum packaged and refrigerated mahi sefid (Rutilus frisii kutum) fillets using an onion (Allium cepa) extract

The combined effect of light salting, vacuum packaging and onion extract on the shelf life of mahi sefid (Rutilus frisii kutum) fillets under refrigeration was assessed using chemical, microbiological and sensory methods. The shelf life of control, air‐packaged, salted (APS), vacuum‐packaged, salted (VPS) and vacuum‐packaged, salted with onion extract (VPSOE) samples was determined to be up to 6, 9, 15 and 18 days respectively. The values of total volatile basic nitrogen, free fatty acid and thiobarbituric acid increased progressively during the storage period for all the treatments. However, the preservative methods applied led to an extended shelf life of fillets based on chemical indices and sensory attributes in the following order: VPSOE>VPS>APS>control group. The assay of the total viable count (TVC) revealed that 2% and 4%VPSOE produced a decrease in TVC throughout the storage period. According to the results obtained, the best method to preserve the mahi sefid fillet was by 4%VPSOE treatment.     

Investigation of Natural Extracts and Sodium Bisulfite Impact on Thermal Signals and Physicochemical Compositions of Litopenaeus vannamei during Chilled Storage

This research work evaluates the impact of 1.2% pomegranate peel extract (Pp) (Punica granatum), 0.1% grapefruit seed (Gfs) (Citrus paradisi) extract, and synthetic preservative 1.25% sodium bisulfite on shelf life extension of Litopenaeus vannamei stored at 4 and 15°C. The application of isothermal titration calorimetry (ITC) for comparison of the extracts and chemical preservative on shrimp quality retention based on the overall heat production by microbial and enzymatic degradation was addressed. The occurrence of probable bioactive responsible for antimicrobial and antioxidant activity components in the extracts was examined through gas chromatography-mass spectrometry (GCMS). At 4°C, Pp-treated shrimps resulted in 6.73 logCFU/g, 6.93 logCFU/g, 5.31 mgN/100 g, and 0.58 mgMDA/kg for aerobic plate count, psychrotrophic bacterial count, trimethylamine, and thiobarbituric-acid reactive substance, respectively, on the 15th day. At 15°C, Pp-coated shrimps retained quality until day 4. Isothermal calorimetric analysis resulted in a rapid and sharp peak for fresh samples, whereas there was broad and delayed peak for shrimp treated with Pp and sodium bisulfite. These observations prove that Pp counterpart the chemical preservative and outperform Gfs on shrimp quality retention. Results also indicate that isothermal calorimetry can be a useful technique for shelf life predictions and comparative evaluation of extract impact on shrimp quality retention.     

Inhibition of Melanosis,Microbial and Quality Changes of White Shrimp (Penaues vannameii) via Effect of Key Lime Juice and Vacuum Packaging at 2 ± 1ºC

This study aimed to investigate the effects of key lime juice (KL) in combination with vacuum packaging (VP) or air storage (SB) on the quality changes of white shrimp stored at 2 ± 1ºC. The quality was assessed using microbiological analysis, color measurement, pH, and total volatile base nitrogen (TVBN). Treatment with KL exhibited inhibitory activity on the growth of spoilage microflora. KL in combination with VP revealed a lower bacterial count in the range of 4.37–4.91 log CFU gˉ¹ on day 12 of storage as compared to other treatments. VP + KL and VP samples could inhibit melanosis. In addition, lower TVBN content was obtained in VP + KL (5.33 mg N/100 g), followed by VP (6.03 mg N/100 g) samples on day 12 of storage (p < 0.05). VP in combination with KL had the lowest loss of quality changes for the white shrimp. Therefore, VP + KL could be used as an alternative preservative method to extend the shelf life for white shrimp.     

Effect of Packaging on Chemical Changes and Quality of Refrigerated Spot (Leiostomus xanthurus)

Spot (Leiostomus xanthurus) were overwrapped with Saran® (PVDC), vacuum skin packaged film-to-tray or film-to-film with Intact® skin packaging film (ISPF), or vacuum packaged film-to-film with surlyn and refrigerated at 4ºC for 15 days. ISPF packaged fish samples had significantly lower ammonia concentrations than overwrapped fish. No significant differences in pH or TBA values were determined among the investigated packaging materials. Vacuum packaging reduced microbiological shelf life of fish by approximately three days when compared to Saran® overwrap. ISPF film-to-film vacuum packaged fish had the longest sensory shelf life, while PVDC overwrapped fish had the shortest.     

Effects of High Pressure Treatment on Physicochemical Quality of Pre- and Post-Rigor Palm Ruff (Seriolella Violacea) Fillets

Fish and fish products are characterized for having a short shelf life. Nonthermal processing techniques such as high hydrostatic pressure (HHP) have increasingly been employed to extend shelf life of food products. The aim of this study was to evaluate changes on flesh physicochemical spoilage parameters (pH, total volatile bases (TVB-N), trimethylamine (TMA), thiobarbituric acid (TBA), and color) of palm ruff (Seriolella violacea) fillets in pre- and post-rigor conditions, subjected to two different HHP conditions: 450 MPa and 550 MPa, for 3 and 4 min each. Unpressurized and pressurized fillets were kept in chilled storage (4 ± 1°C) for 26 days to assess the effect of HHP on shelf life. pH and TBA values increased after HHP treatment and with storage time for both unpressurized and pressurized samples. This is attributable to pressure-induced lipid oxidation. Lightness (L*) values increased with pressure, where fish fillets had a cooked appearance. TMA and TVB-N values decreased after HHP treatment compared to the unpressurized samples, showing that HHP treatment is an efficient method to maintain the quality of palm ruff fillets. There was no clear difference between pre- and post-rigor in the parameters evaluated.     

Effects of Natural and Artificial Colorants on Hot Smoked Garfish—Belone belone (Linnaeus, 1761)—Stored at 4 ± 1ºC

In this study, the effects of natural and artificial colorants on the shelf life of hot smoked garfish were investigated in terms of its chemical, microbiological, and sensory quality. Turmeric and Sunset Yellow FCF were used as the natural and artificial colorants, respectively. The amount of total volatile basic nitrogen (TVB-N) and thiobarbituric acid (TBA), counts of total mesophilic aerobic bacteria, total psychrophilic aerobic bacteria, total yeast and molds increased during the storage (p < 0.05). The results showed that turmeric and Sunset Yellow FCF had a significant effect on pH value and salt content of hot smoked garfish samples during storage (p < 0.05). According to the sensory analysis results, the shelf life of hot smoked garfish stored at 4 ± 1ºC was determined as 17 days.     

Effect of Delayed Icing on the Microbiological,Chemical, and Sensory Properties of Caspian Sea Golden Grey Mullet (Liza aurata)

Research has shown that fresh fish is an extremely perishable food as compared to other food commodities. In this study, quality deterioration during storage of golden grey mullet (GGM) iced for 0, 6, and 12 h after landing was monitored. Microbiological indices (total viable count, TVC; psychrophilic counts, PTC; lactic acid bacteria, LAB; and Enterobacteriaceae counts, EBC), chemical parameters (pH; total volatile basic nitrogen, TVB-N; peroxide value, PV; thiobarbituric acid, TBA; and free fatty acids, FFA) values increased over the preicing duration. Delayed icing did not lead to significant increases (p > 0.05) in TVC, PTC, LAB, and EBC throughout the period of storage. All chemical indices increased during storage (p < 0.05). This study showed that sensorial analysis of GGM correlated well with microbiological analysis. Results of this study based on the microbiological and raw fish sensorial data indicated that the shelf life of GGM stored in ice immediately after catch was approximately 10–11 days, while the 6- and 12-h delays in icing shortened the shelf life to approximately 6–7 and 2–3 days, respectively.     

Optimization of Ozonated Water Treatment of Wild-Caught and Mechanically Peeled Shrimp Meat

ABSTRACT

Ozone is a USFDA and USDA approved food contact sanitizing agent and has been used in the seafood industry in both gaseous and dissolved forms to destroy bacteria. The wild harvest shrimp industry is the most economically important fishery in the U.S. Gulf of Mexico region, and in Louisiana the majority of the harvest is mechanically peeled and frozen. Dissolved ozone was measured in processing water at product application to study the optimization of ozonated water treatment for reducing microbial contamination of peeled shrimp meat. Shrimp samples were either sprayed or soaked in water with 1, 2, and 3 ppm dissolved ozone. Treatment times of 20, 40, and 60 seconds were investigated for all applications and concentrations. Similar volumes of water were applied for all treatments, and soaking showed greater bacterial reduction than spray treatments for all time and concentration combinations studied. Soaking in 3 ppm dissolved ozone for 40 s and 60 s showed the greatest reduction of total aerobic bacteria, and 60 s at 3 ppm resulted in the greatest reduction of Pseudomonas bacteria. Ozonated water treatment did not produce oxidation in the shrimp samples. The optimal treatment of soaking shrimp in 3 ppm dissolved ozone for 60 s will be used for further investigations of refrigerated shelf life extension and Listeria monocytogenes destruction in peeled shrimp meat.     

Evaluation of three non‐genetically modified soybean cultivars as ingredients and a yeast‐based additive as a supplement in practical diets for Pacific white shrimp Litopenaeus vannamei

Two growth trials and a physiology assessment were conducted to evaluate three non‐genetically modified (GM) soybean cultivars as ingredients in practical diets for Pacific white shrimp, Litopenaeus vannamei. In addition, a commercially available fermented yeast product was evaluated as dietary supplement. For the growth trials (46 and 35 days, respectively, for trials 1 and 2), the basal diet was primarily composed of soybean meal (SBM), fishmeal (FM), whole wheat, corn protein concentrate, poultry meal (PM, pet food grade) and corn starch. Non‐GM cultivars were processed with novel methodologies to produce Navita? ingredients (N1, N2 and N3) which were incorporated at low (L) or high (H) levels into the experimental diets, in partial replacement of FM and full replacement of conventional SBM. The last two formulations incorporated the fermented yeast for a total of nine experimental diets (Table 1 ). Results from the growth trials indicate that shrimp fed diet 5 (HN2) exhibited significantly lower (p < .05) weight gain as compared to shrimp fed diets 1 and 2 (basal and LN1, respectively) in trial 1, as well as compared to animals fed diets 1, 2, 3 and 8 (basal, LN1, HN1 and basal + yeast) in trial 2. The feed conversion ratio significantly increased for shrimp fed diet 5, in contrast with shrimp fed diets 1, 2, 3 and 8 in trials 1 and 2, as well as compared to shrimp fed diets diet 6 (LN3) in trial 2. For the physiological assessment (stress and immune responses), only the effects of diets 1, 3, 8 and 9 (basal, HN1, basal + yeast and HN1 + yeast, respectively) were investigated. Granular cell counts were significantly higher for shrimp fed the yeast‐containing diets. Haemolymph glucose and haemolymph packed cell volume were significantly reduced for shrimp fed diets 3, 8 and 9. No significant differences were observed in total haemocyte counts, hyaline cells counts, semi‐granular cells counts, haemolymph protein, haemocyte phagocytic capacity and haemocyte respiratory burst activity. Results of this work indicate that selective soy breeding technology coupled with novel processing options has the potential to increase the nutritional value of conventional SBM for shrimp feeds. Trends on immune responses were more difficult to elucidate possibly due to the limited length of the feeding trial.     

Evaluation of the Shelf Life of Tambaqui Fillet Processed by the Sous Vide Method

This study aimed to elaborate a convenience food – sous vide – and establish its shelf life by monitoring physicochemical, microbiological, and sensorial characteristics. Sous vide fillets were prepared from tambaqui (Colossoma macropomum) with two types of sauces: soy sauce (SS) and basil sauce (BS), at a pasteurization temperature of 65°C for 12.5 min, a binomial established according to a 2² central composite rotational design. The packed samples were kept under refrigeration in the range of 1 ± 1°C, and then they underwent analyses at 7, 14, 21, 28, 35, 42, 49, and 56 days of storage. The results of the microbiological analyses indicated that microorganisms remained below acceptable limits either in the raw material or in the sous vide over the storage period. The characteristics that sous vide SS and BS showed on the 42nd and 49th days of shelf life, respectively, indicate that these products, when appropriate processing and storage are used, can preserve their fresh quality.     

Effect of Lead on Survival,Osmoregulation, and Histological Changes of the Gills of the White Shrimp,Litopenaeus vannamei,Boone, 1931

The purpose of this study was to evaluate the acute toxicity of lead for different life stages of shrimp, Litopenaeus vannamei, and to determine the effect of its sublethal concentrations on osmoregulatory capacity (OC) as well as the possible histological alteration in the gills of juvenile shrimp. The 24‐, 48‐, and 96‐h LC₅₀ values for lead to L. vannamei increased progressively with increasing life stage, from nauplii < zoeae < mysis < postlarvae < juvenile. After 15‐d exposure to 3.25, 6.50, and 9.75 mg Pb/L, the OC values of exposed shrimp were reduced by 39, 73, and 157%, respectively compared to control animals. Compared to controls, the lead concentrations in gill tissues increased significantly by 127,500, 137,500, and 141,000% in shrimps exposed to 3.25, 6.50, and 9.75 mg Pb/L, respectively. After lead exposure, hemocytic congestion in efferent vessels and multiple hyperplasia were observed in gill filaments, resulting in narrowed hemolymphatic lacuna. The histopathological effects increased with increasing Pb concentration.     

Quality and Shelf Life Assessment of Puffer Fish (Lagocephalus guentheri) Fillets during Chilled Storage

The aim of the study was to quantify the shelf life and quality characteristics of puffer fish, Lagocephalus guentheri, fillets on chilled storage at 2 ± 1°C. The puffer fish muscle contains 16.14% protein, 80.76% moisture, 0.99% ash, and 0.17% fat. The mouse bioassay proved the absence of tetradotoxin in muscle, liver, skin, and gonads of the fish. The polyunsaturated fatty acid to saturated fatty acid (P/S) ratio of puffer fish was found to be 1.3, with n-3 to n-6 ratio of 3.27. The puffer fish had hypocholesterolemic/hypercholesterolemic ratio (H/H) value of 2.68, artherogenicity index of 0.43, and thrombogenicity index of 0.29. Beheaded and deskinned fishes were filleted and were studied for 10 days of chilled storage. The physical, chemical, sensory, and microbiological parameters showed significant (p < 0.05) changes during the entire storage period. While the hydrolytic rancidity was significantly correlated to springiness, gumminess, and chewiness of fillets, the peroxide value (PV) correlated with the color attributes and pH. The hardness of the samples decreased significantly and was evident in both sensory and instrumental analysis. With storage time, the yellowness of the fillets increased steadily. The results of this study can help in improving processing, preservation, and marketing aspects and enhance the utility of puffer fish.     

Effects of dietary β‐glucan and glycyrrhizin on non‐specific immunity and disease resistance of white shrimp,Litopenaeus vannamei (Boone) challenged with Vibrio alginolyticus

The white shrimp Litopenaeus vannamei, fed immunostimulant‐free, 0.2%β‐glucan and 0.06% glycyrrhizin diets for 18 days, respectively, were challenged with Vibrio alginolyticus at 6.4 × 10⁴ CFU shrimp^?1. The total haemocyte count (THC), phenoloxidase (PO) activity, respiratory burst (RB) and superoxide dismutase (SOD) activity changes for a 120‐h period were investigated, and shrimp mortality was also recorded. The results showed that PO activity, RB and SOD activity were significantly higher in shrimp fed the two immunostimulant diets after 18 days than those in shrimp fed immunostimulant‐free diets. The THC and SOD activity decreased significantly from 0 to 24 h post challenge, and then reverted to normal levels at 96 and 72 h respectively. The values for PO activity and RB increased from 0 to 48 h post challenge. Compared with those fed the control diets, shrimp fed immunostimulants had significantly higher PO activity and RB values at 120 h post challenge. Mortalities after challenge with V. alginolyticus were significantly lower in shrimp fed with β‐glucan or glycyrrhizin than in those fed with a diet without immunostimulants. It was concluded that dietary β‐glucan and glycyrrhizin increased the shrimp immunity. Furthermore, β‐glucan caused an increase in some immune parameters 12 h earlier than glycyrrhizin after V. alginolyticus challenge.     

Effects of Modified Atmospheric Packaging Conditions on the Quality Changes of Pasteurized Oyster (Crassostrea belcheri) Meat during Chilled Storage

ABSTRACT

The effects of different atmospheric conditions on the quality and the shelf life of pasteurized oyster meat in chilled storage were investigated. The alternatives tested for pasteurized oyster meat were normal air (Control), 75% CO₂/25% N₂ (MAP-1), 75% CO₂/25% O₂ (MAP-2), 75% CO₂/5% O₂/20% N₂ (MAP-3), and vacuum packing (VP). The various observations of microbiological (total viable count (TVC), Enterobacteriaceae, Pseudomonas spp., lactic acid bacteria (LAB), and hydrogen sulfide–producing bacteria), physical (color coordinates L*, a*, and b*, and cutting strength), chemical (moisture, pH, total volatile basic nitrogen (TVB-N), peroxide value (PV), and thiobarbituric acid reactive substances (TBARS)) and sensory properties were performed every 3 days over a total of 27 days. During storage across all the treatments, L*, a*, cutting strength, pH, moisture content, and sensory scores decreased; whereas, b*, TVB-N, PV, TBARS, and microorganisms increased. However, among the various alternatives, MAP-1 had the best retention of oyster quality during storage. Based on sensory and microbiological qualities, the shelf lives in chilled storage were 9 days for control, 15 days for VP, 21 days for MAP-2 and MAP-3, and 24 days for MAP-1-treated cases.     

Effects of feeding live or frozen prey on growth, survival and the life cycle of the cuttlefish, Sepia officinalis (Linnaeus, 1758)

The effects of feeding live or frozen grass shrimp (Palaemonetes varians) to the cuttlefish, Sepia officinalis, were determined in two experiments. During Experiment I, two populations of 30 cuttlefish (aged 90 days old) were fed either live or frozen grass shrimp. Cuttlefish fed live shrimp grew larger, matured earlier, had a shorter life cycle (255 days) than the ones fed frozen shrimp (282 days), and had lower mortality. Females from the group fed frozen shrimp matured a month later but were significantly larger, 130.9 ± 38.5 g, compared to 74.2 ± 16.0 g, laid larger eggs, 0.47 ± 0.11 g, compared to 0.28 ± 0.10 g, and had higher individual fecundity (411 eggs female⁻¹, compared to 150 eggs female⁻¹). Newly born hatchlings from both groups had similar weights. During Experiment II, six replicates of 15 cuttlefish (50 days old) were used, three for each of the two diets tested. The exact same amount of live or frozen shrimp was provided to both populations twice a day. No differences in growth and feeding rates or food conversions were found at the end of the experiment. During the first week, cuttlefish fed frozen shrimp grew larger, and had higher conversion rates, compared to the ones fed live shrimp. Mortality was higher for the group fed live shrimp (36.6%) in Experiment II, mainly occurring during the last week. Mortality for cuttlefish fed frozen shrimp in Experiment II was 2.2%. Results obtained here indicate that freezing the grass shrimp only had a negative effect on the survival of S. officinalis in Experiment I. This revised version was published online in August 2006 with corrections to the Cover Date.     

The chemical and sensorial changes in rainbow trout caviar salted in different ratios during storage

In this study, the intention was to investigate the chemical and sensorial changes occurring during cold storage (4 ± 1°C) of caviar obtained from rainbow trout Oncorhynchus mykiss W. 1792 that was dry salted in different ratios. Caviar has a higher fat and protein content than other seafood products, and in processing it with dry salting technology, it was determined that the shelf life could be up to 28 days for the experimental group in which salt was applied at a rate of 4% and up to 35 days for the experimental group in which salt was applied at a rate of 8%. Thus the storage period of the samples is longer for the products to which a high (8%) amount of salt was applied than the products to which a low (4%) amount of salt was applied in the salting process.     

Reflecting on the Recent Publisher's Report

Research was conducted to determine the effects of potassium sorbate applications (0, 1, 3, and 5% w/v) on the shelf life of pearl mullet (?nci Kefali; Chalcalburnus tarichi) fillets packaged with vacuum. Fillets kept at 4 ± 1°C were subjected to microbiological (total aerobic mesophilic bacteria, psychrotrophic bacteria, lactic acid bacteria, Enterobacteriaceae, molds, and yeasts) and chemical (pH, thiobarbituric acid—TBA, total volatile base nitrogen—TVB-N, water activity, and biogenic amines) analyses on certain days (0, 3, 6, 9, and 12 days) of storage. It was determined that potassium sorbate had effects on total aerobic mesophilic bacteria, psychrotrophic bacteria, Enterobacteriaceae, mold-yeast counts, TVB-N values, phenylethylamine, putrescine, tryptamine, and pH of fillets at a significant (p < 0.01) degree. Retarded bacterial growth was observed as the antimicrobial effect increased with the degree of its concentrations. Storage time had significant (p < 0.01) effects on bacteria count, TBA, TVB-N values, and biogenic amines; all of which were increased by longer storage. It was concluded that application of potassium sorbate, especially at a 5% level, and vacuum packaging helps cold stored fillets maintain their biogenic amines and microbiological and chemical qualities longer.