Comparative Variations of Extractive Nitrogenous Components and Quality in Fresh Muscle and Dried Product of Rabbitfish (Siganus fuscescens) in Taiwan

ABSTRACT

Variations in the level of quality and extractive nitrogenous components were investigated in the fresh muscle and commercial dried products of rabbitfish Siganus fuscescens collected from Penghu, Taiwan. The respective freshness quality for fresh muscle is as follows: trimethylamine oxide (TMAO), 29.50 mg N/100 g; trimethylamine (TMA), 2.30 mg N/100 g; NH₃, 6.61 mg/100 g; total volatile basic nitrogen (TVBN), 13.32 mg/100 g; aerobic plate count, 1.53 log CFU/g; and K-value, 28.80%. The respective freshness quality for dried products is as follows: TMAO, 43.44 mg N/100 g; TMA, 25.56 mg N/100 g wet wt.; NH₃, 52.00 mg/100 g wet wt.; TVBN, 149.98 mg/100 g; aerobic plate count, 4.16 log CFU/g; and K-value, 89.73%. The major fatty acids in the fresh muscle and dried products are C16:0, C18:1 n-9, C18:0, C16:1 C22:6 n-3, and C22:5 n-3. The major nucleotide compound is inosine 5?-monophosphate (IMP) in the fresh muscle (68%) and hypoxanthine (Hx) in the dried products (79%). The level of total free amino acids in the dried products shows significant variation depending on the processing method of the plants.     

Effect of Chitosan and Garlic Essential Oil on Microbiological and Biochemical Changes that Affect Quality in Grass Carp (Ctenopharyngodon idellus) Fillets During Storage at 4°C

Solutions of chitosan (2%, w/v), garlic essential oil (5%, v/v), and their combination (2%, w/v chitosan +5%, v/v garlic essential oil) were applied to the surface of grass carp fillets. Subsequently, sensory, microbiological analyses (total viable count (TVC), Pseudomonas spp., Aeromonas spp., and H₂S-producing bacteria), and physicochemical changes (total volatile basic nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARS), and centrifugation loss) of grass carp fillets were evaluated over a 16-day storage at 4 ± 1°C. The treated samples resulted in significantly (p < 0.05) higher overall acceptance scores than the control from day 8. The TVC of grass carp fillets was reduced from the initial level (4.0 log CFU/g) to 2–3 log CFU/g when the fillets were treated with either garlic essential oil or chitosan solution. After 4 days of storage, the Pseudomonas spp. counts in the chitosan-treated samples were significantly lower (p < 0.05) than the counts in control and samples treated with garlic essential oil. A lag phase of 6 days for the counts of H₂S-producing bacteria of fish fillets that were treated with chitosan or the combination solution was observed. The combination of chitosan with garlic essential oil did not show synergistic effects, although it displayed a higher degree of antimicrobial efficacy with respect to the spoiled bacteria. However, the combination of chitosan with garlic essential oil was the most effective at inhibiting the formation of TVB-N. Samples that were treated with garlic essential oil displayed the highest TBARS levels on days 4 and 6 (p < 0.05).     

Leiopathes glaberrima millennial forest from SW Sardinia as nursery ground for the small spotted catshark Scyliorhinus canicula

1. Association between habitat structuring organisms and other species has great relevance for ecosystem‐based conservation measures.
2. Those occurring in temperate areas, particularly in the upper portion of the continental margin, are mostly unknown or not properly understood because of the difficulty to discriminate co‐occurrence and real functional linkages among species.
3. Deep water coral assemblages over the Carloforte Shoal (south‐west Sardinia; 180–210 m depth) were investigated using ROV surveys.
4. During the surveys, more than 740 egg‐capsules of the spotted catshark Scyliorhinus canicula, identified after hatching experiments in captivity, were found attached exclusively to colonies of the long‐living black coral Leiopathes glaberrima.
5. Although based on a spot finding, the results show that coral forests are not only hotspots of biodiversity, but can also serve as nursery grounds for S. canicula. The protection of these millennial coral forests is therefore to be considered a priority.

     

Physicochemical,Microbiological, and Sensory Properties of Pâté Elaborated from Whitemouth Croaker (Micropogonias furnieri) Muscle

The aim of this research was to formulate a unique product, croaker pâté, and to determine its physicochemical, microbiological, and sensorial characterization. Three formulations of pâté were elaborated. The pâtés fit in the stipulated regulations for the microbiological test. Regarding the texture, the pâtés presented a significant difference (p < 0.05) among each other. In the sensorial tests, the favorite pâté of the panel was formulation 3; in the acceptance test, it had higher levels of acceptance for color, flavor, and global acceptance in comparison with commercial pâté.     

Physicochemical and Microbiological Assessment of Ready-to-Eat Tuna Döner Kebab During Marination,Cooking, and Different Storage Conditions

ABSTRACT

The aim of this work was to investigate the use of bluefin tuna (Thunnus thynnus) in ready-to-eat döner kebab production and determine the effects of marination, cooking, and storage conditions (4 and ?18°C) on physicochemical and microbiological properties of döner kebab. The raw tuna meat and raw, cooked, and stored döner kebab samples were subjected to moisture, protein, fat, ash, pH, cholesterol, biogenic amines, lipid oxidation, fatty acids profile, microbiological, and sensory analysis. The major fatty acids in tuna döner kebab were palmitic, stearic, oleic, omega-3, and omega-6 fatty acids; unsaturated fatty acids were higher than saturated fatty acids (p < 0.05). Low biogenic amine and cholesterol contents were determined in döner kebab. While cooking affected the proximate composition, microbial load, and the levels of histamine and tyramine (p < 0.05), marination did not have any significant effect. The study results indicated that using tuna meat in döner kebab production could be an alternative approach to provide new seafood products without posing any acceptability problems in terms of quality factors.     

Impact of Feeding Status on the Efficacy of Depuration for Decontaminating Vibrio parahaemolyticus in Pacific Oysters (Crassostrea gigas)

Vibrio parahaemolyticus causes acute human gastroenteritis and is often linked to consumption of raw oysters. Previous investigations indicated that refrigerated seawater depuration at 12.5°C could significantly reduce V. parahaemolyticus contamination in Pacific oysters; however, further optimization is necessary to achieve the regulatory target of >3.52 log most probable number (MPN)/g reduction. The current study investigated influences of algal feeding on efficacy of depuration to reduce V. parahaemolyticus in raw oysters. A V. parahaemolyticus cocktail (10290, 10292, 10293, BE 98–2029, 027-1c1) was mixed in artificial seawater (70 L) to inoculate oysters (n = 35) at 4–5 log MPN/g. Inoculated oysters were subjected to depuration with feed (algae = 0.036 ml/gram of oyster) and without feed at 12.5°C. Oysters (n = 5) were analyzed for V. parahaemolyticus using a three-tube MPN method after 0, 1, 3, 5, and 6 days of depuration. Depuration (6 days) achieved average V. parahaemolyticus reductions of 2.75 log MPN/g and 3.03 log MPN/g in the fed and unfed systems, respectively; however, feeding status did not significantly impact the efficacy of depuration to reduce V. parahaemolyticus in Pacific oysters. Further optimization of depuration is necessary to achieve the regulatory target for V. parahaemolyticus decontamination in raw oysters.     

Changes in the Chemical Characteristics of Gulbi,Salted and Dried Yellow Corvenia,During Drying at Different Temperatures

A few chemical characteristics of Gulbi, a traditional Korean seafood prepared from salted and dried Yellow corvenia (Pseudosciaena manchurica), were investigated during drying at different temperatures. When Gulbi was manufactured by sun-drying (the control), it had the highest thiobarbituric acid reactive substances (TBARS) and volatile basic nitrogen (VBN) values. They increased with increasing drying time at all temperatures in the hot-air drier. The TBARS value of Gulbi was lower when dried at 30 and 35°C than at 40°C and the control. The VBN of the control was higher than that of hot-air dried Gulbi at 30 and 35°C and lower than that of hot-air dried Gulbi at 40°C. The control had a VBN value of 20.8 ± 0.07% and the hot-air dried at 30°C, 18.0 ± 0.06; at 35°C, 18.6 ± 0.06; at 40°C, 23.8 ± 0.08 (p < 0.05), respectively. The salt content of the control and Gulbi dried at 30, 35, and 40°C were 22.9 ± 0.07%, 17.7 ± 0.06%, 18.0 ± 0.06%, and 24.3 ± 0.08%, respectively. The amino nitrogen content was much lower: 63.1 ± 0.80 mg/100 g and 65.5 ± 0.14 mg/100 g at 30 and 35°C than 78.3 ± 0.21 mg/100 g at 40°C. The results of this study also indicate that the Gulbi dried at 30 and 35°C had better chemical characteristics than those dried at 40°C when using hot-air drying and sun drying.     

Biochemical and Microbiological Assessment of Crucifix Crab (Charybdis feriatus) Stored at 4°C

Charybdis feriatus is a highly prized crab in the local and international markets of East Asian countries. In local markets, crabs are sold live, iced, or refrigerated at 2°C – 4°C. The present study was carried out to determine the shelf life of whole crab stored at 4°C for 192 h using a set of biochemical, microbiological, and sensorial parameters. Biochemical indicators such as the total volatile base nitrogen (TVB-N) and trimethylamine nitrogen (TMA-N) increased significantly during storage and within an acceptable limit up to 144 h. Regarding the biogenic amines, cadaverine and spermidine increased significantly (p < 0.05) during the storage period. Among them, cadaverine could be proposed as a useful spoilage indicator for this crab species. The mesophilic and psychotropic bacterial count exceeded the limit of acceptance after 144 h of storage. Sensory attributes were gradually diminished with the storage time. Sensory scores were found to correlate well with both mesophiles and psychrotrophs. Based on the results of this study, the meat quality of Charybdis feriatus can be maintained up to 144 h when properly stored at a temperature of 4°C ± 1°C.     

Formation of Biogenic Amines in Delayed Salt-Cured Whole and Gutted Indian Oil Sardines (Sardinella longiceps)

The formation of biogenic amines in Indian oil sardines (Sardinella longiceps) collected from the Tuticorin coast of South India and treated with delayed salt-curing was investigated. Sardines were wet salt-cured in whole and gutted forms and examined in fresh and after 6, 9, 12, and 15 h delayed conditions at ambient temperature (32 ± 2°C) at four stages of salt-curing process for quality parameters and formation of biogenic amines. Moisture content decreased from 76% to 11.3% in salting followed by drying. Similarly, water activity reduced from 0.96 to 0.74 in salt-cured sardines. In contrast, total volatile base nitrogen content increased from 79 to 3,590 mg kg^–1 in salt-cured sardines. Halophilic count of sardines was higher (8 log cfu g^–1) after salting and decreased in drying stages. The 15 h delayed salt-cured whole sardines had higher histamine contents (1,568.27 mg kg^–1), cadaverine (4,059.84 mg kg^–1), putrescine (1,604.95 mg kg^–1), and tyramine (862.94 mg kg^–1) on the final day of drying. Whole sardines had higher biogenic amines and halophilic bacterial counts than the gutted sardines. The whole and gutted sardines salt-cured up to a delay of 6 and 12 h, respectively, at ambient temperature yielded the acceptable quality products with respect to biogenic amines.     

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.     

Microbiological controls across the productive cycle of Dicentrarchus labrax L. and Sparus aurata L.: a study from the environment to the final product

The microbiological quality of water, sediments and seafood products of three Sicilian marine fish farms (Castellammare Gulf, Capo d'Orlando and Porto Palo) was investigated in order to draw a complete picture of the health conditions from the start (environment) to the end (seafood product) of the productive cycle. Before the beginning of fish farming, low concentrations of faecal contamination indicators (faecal coliforms, Escherichia coli, enterococci) were found in the water of each examined area. Due to the enhanced organic load released from cages, the set‐up of fish farming significantly altered the distribution of faecal indicators and sometimes that of halophilic vibrios in the pelagic compartment. Significant differences in the density of heterotrophic bacteria were sometimes recorded at the sediment level. Despite this increase in microbial abundance, the microbiological conditions remained acceptable for the productive process. Pathogens (Salmonella spp., Vibrio parahaemolyticus, Listeria monocytogenes, Staphylococcus aureus) were mostly absent in seafood products. The study underlines that the achievement of good quality levels in aquaculture strongly depends on the conformity of the rearing environment to qualitative microbiological standards, highlighting the importance of sanitary controls along the different steps of the productive cycle.     

Dried leaves of Rosmarinus officinalis as a treatment for streptococcosis in tilapia

Dietary application of dried Rosmarinus officinalis (rosemary) leaves as a treatment for streptococcal infection was studied in tilapia, Oreochromis sp. Feeding with dried rosemary leaves significantly reduced mortality following infection with Streptococcus iniae: 44% mortality in the group fed 8% rosemary, similar to oxytetracycline treatment (43% mortality), and significantly lower than the control (65%). Dietary administration of 16% rosemary significantly reduced mortality because of Streptococcus agalactiae infection in 44 g fish (62% and 76% in 16% rosemary and control, respectively), but not in a similar experiment conducted with 5.5 g fish. The antibacterial effect of rosemary on S. iniae was studied. Activity of rosemary cultivar Israel was reduced during the winter, but there was no significant change in cultivars Oranit and Star. Storage of powdered rosemary leaves at 50 °C resulted in fourfold and eightfold higher MIC_{24 h} values after 3 and 4.5 months, respectively. Storage at ?20 °C, 4 °C and 25 °C and autoclaving (120 °C) each resulted in a twofold increase in MIC_{24 h}. Repeated exposures of S. iniae to rosemary did not affect minimal inhibitory concentration, suggesting no development of resistance to rosemary.     

Improving the Quality of Silver Carp Fish Fillets by Gamma Irradiation and Coatings Containing Rosemary Oil

The objective of this work was to study the combined effect of gamma irradiation and coatings containing 0.5% rosemary (Rosmarinus officinalis) essential oil (RO) on the chemical, microbiological, and sensorial qualities of silver carp (Hypophthalmichthys molitrix) fish fillets (SFF) during cold storage (4°C). SFF were divided into three groups: uncoated (control), coated with edible coating (without additives), and γ-irradiated (0, 1, 3, and 5 kGy) coated with coating containing 0.5% rosemary. Gamma irradiation at 1, 3, and 5 kGy with coating reduced the initial total bacterial count, psychrophilic bacteria, and lactic acid bacteria and prolonged shelf life of the samples. Coated samples irradiated at 1 kGy reduced the counts of Enterobacteriaceae, Staphylococcus aureus, and Bacillus cereus, as well as eliminating Vibrio spp. and Salmonella spp., while coated samples irradiated at 3 and 5 kGy completely eliminated these bacteria. Combined treatment showed a slight increase in thiobarbituric acid-reactive substances postirradiation during cold storage but had no effect on the total volatile basic nitrogen and trimethylamine contents, while a gradual increase in these chemical quality indices was observed during cold storage. Combined treatment had no adverse effects on the sensory properties of SFF. The increase in the bacterial inhibitory effect is caused by both rosemary oil and irradiation.     

Histamine formation in flying fish contaminated with <Emphasis Type="Italic">Staphylococcus xylosus</Emphasis>

Histamine is the main causative agent of scombroid poisoning. However, unlike scombroid fish, histamine poisoning due to consumption of flying fish has never been reported. In this study, the white muscle of flying fish had high levels of free histidine at approximately 423.9 mg/100 g, and was inoculated with Staphylococcus xylosus Q2 isolated from dried flying fish at 5.0 log CFU/g and stored at ?20 to 35°C to investigate histamine-related quality. The histamine contents quickly increased to higher than 50 mg/100 g in samples stored at 25 and 35°C within 12 h as well as stored at 15°C within 48 h. However, bacterial growth and histamine formation were controlled by cold storage of the samples at 4°C or below. Once the frozen flying fish samples stored at ?20°C for 2 months were thawed and stored at 25°C after 24 h, histamine started to accumulate rapidly (>50 mg/100 g of fish). Therefore, flying fish muscle was a good substrate for histamine formation by bacterial histidine decarboxylation at elevated temperatures (>15°C) when it is contaminated with S. xylosus. In conclusion, since the improperly contaminated flying fish muscle with S. xylosus could lead to production of hazardous levels of histamine over time when stored at temperatures >15°C, the flying fish should be stored below 4 °C or below to control proliferation of S. xylosus, and TVBN and histamine production.     

Influence of Monascus Fermentation on Storage Characteristics of Semidry Salted Tilapia

Semidried salted tilapia was fermented and prepared by Monascus (Monascus anka and Monascus purpureus). The sample was restored at 25°C to undergo the preservation test. The color value, total volatile base nitrogen (TVB-N) value, ammoniacal nitrogen content, acid value, and peroxide value were measured on a daily basis for 24 days. Results showed that Monascus contributed to inhibiting the growth of microorganisms and delayed the advent of decomposition. Meanwhile, they could keep the lipids from oxidation and rancidity, which helped the semidried tilapia achieve a satisfying color. The preservation test and the bacterial colony culture test on physicochemical and microbiological indexes under 25°C showed that Monascus fermentation could inhibit the growth of other microorganisms, improved the quality of semidried tilapia, and extended shelf life.     

Investigation of the Protective Effect of β-carotene in the Prevention of Lipid and Protein Oxidation in Carp Meat during Different Storage Times

ABSTRACT

This study was aimed to investigate the effects of dietary β-carotene supplement for 42 days on lipid and protein oxidation biomarkers in carp meat at different times of storage. Seventy-five fish were divided into three groups: group 1 as control group was fed with basic diet; groups 2 and 3 received 50 and 100 mg kg^?1 diet β-carotene, respectively. Based on the present study results, muscle malondialdehyde concentrations were significantly lower following β-carotene consumption at 0, 24, 72, and 96 h after harvest in group 3 compared to the control group (p < 0/05). Muscle protein carbonyl contents showed a significant decrease following β-carotene supplementation at 0, 48, and 96 h after harvest in group 3 compared to the control group. Ferric reducing antioxidant power values were significantly increased following β-carotene supplementation at 72 and 96 h after harvest in group 3 compared to the control group. The results indicated that β-carotene supplementation with a dose of 100 mg kg^?1 diet is largely effective to improve the oxidative status of carp meat by reducing lipid and protein oxidation.     

Listeria monocytogenes is inhibited on fillets of cold‐smoked sunshine bass,Morone chrysops × Morone saxatilis,with an edible corn zein‐based coating incorporated with lemongrass essential oil or nisin

Ready‐to‐eat (RTE) foods have been identified as a high‐risk food group because of the number of outbreaks caused by food‐borne pathogens isolated from these products. As these items receive no further processing or heat treatment prior to consumption, bacterial pathogens such as Salmonella, Staphylococcus aureus, Escherichia coli, and Listeria monocytogenes present a serious threat to consumer safety. Of particular concern, L. monocytogenes is resistant to various food storage techniques, including reduced or modified atmosphere packaging, refrigerated storage, and increased salt concentration. Cold‐smoked fishery products have been implicated in a number of listeriosis cases, where it is estimated that between 6 and 36% of cold‐smoked fish is contaminated with L. monocytogenes. Edible coatings incorporated with natural antimicrobials have been suggested to control pathogenic and spoilage bacteria on a variety of meat products. In this study, edible zein‐based coatings incorporated with nisin and lemongrass essential oil (LG) (8%) were evaluated for antibacterial action against L. monocytogenes and spoilage organisms on cold‐smoked, cultured hybrid striped bass, Morone saxatilis × Morone chrysops, under polyvinyl chlorine (PVC) and vacuum packaging for 14 days (PVC) and 42 days (vacuum packaging), respectively, at 4°C. In this study, corn zein‐based edible coatings were found to be an effective carrier for nisin and LG. Nisin‐treated samples were most effective against L. monocytogenes in both PVC and vacuum‐packaged fillets, with a total reduction of 3.5 log and 3.7 log, respectively over the length of the storage time. LG‐treated samples reduced L. monocytogenes cell counts by 2.5 log in PVC and 1.7 log in vacuum‐packaged samples. Only LG‐treated samples packaged in PVC were found to inhibit the growth of spoilage organisms. Because nisin‐ and LG‐treated fillets reduced L. monocytogenes, they may be useful methods to improve food safety in smoked seafood.     

Effect of Traditional and Liquid Smoke on the Quality of Sea Catfish Sausages (Sciades herzbergii,Bloch, 1794)

ABSTRACT

Smoking is a technique used to improve the sensory attributes and increase the shelf life of fish. The objective of the present study was to evaluate the nutritional, physicochemical, microbiological, and sensory characteristics of sausages made with sea catfish (Sciades herzbergii) fillets subjected to the traditional and liquid smoking processes. The traditionally smoked sausages showed lower (p < .05) moisture content and higher protein, fat, and mineral levels, higher weight loss during processing, higher pH, higher a* (red intensity), and lower L* (luminosity) values. The percentage of shrinkage, water holding capacity, water activity, hardness, cohesiveness, and elasticity were not influenced (p > .05) by the smoking methods tested. The microbial counts of both treatments were in compliance with the current Brazilian legislation. The sensory acceptance of the liquid smoked sausages was higher (p < .05) when compared to the traditionally smoked sausages for the attributes of color, aroma, texture, flavor, and overall acceptance, with scores ranging from 6 (liked slightly) to 7 (liked moderately). Between the two smoking methods tested, liquid smoking presented better sensory acceptance, easier execution, greater process control, and less environmental impact; thus, it is a viable alternative to the traditional smoking of sea catfish (Sciades herzbergii) sausages.     

Intra-cohort cannibalism among larval stages of perch (Perca fluviatilis)

Cohorts of perch larvae, hatched within 24 h, developed into a bimodal body size distribution as early as 6 days after commencement of external food uptake. At this development stage, intra-cohort cannibalism occurred among larval perch individuals of larval stage V (body size: 10.5±0.26 mm, 95% c. l.) on smaller siblings. In experimental trials the consumption rate (C: no. of prey/predator·hour) increased exponentially with size of predatory perch (L: mm) and at 21°C was expressed by the relationship log C=3.406·log L-3.848 (n=10, r²=0.98, P<0.001). For predatory perch in larval stage V, consumption rate was reduced when Daphnia pulex were added, while not in later stages. Perch larvae experimentally forced to live as true piscivores without additional food items developed from stage V to stage IX (15.8±1.34 mm) within the same time as those fed on Daphnia alone, but with increased mortality.