• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.2
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• pp.120-129
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• 2017

This study assessed the safety of raw oysters Crassostrea gigas for consumption during processing in a processing plant. Bacterial contamination (e.g., viable cell counts, coliform groups, Escherichia. coli and pathogenic bacteria) and chemical contamination (e.g., heavy metals and shellfish toxins) were measured on raw oysters, a processing equipment, employees and work areas. No total mercury, lead, paralytic shellfish poison, diarrheic shellfish poison or norovirus was detected in any post-harvested oyster samples. However, the cadmium level ranged from 0.1-0.2 mg/kg. The viable cell count, E. coli and coliform group levels in post-harvested oysters ranged from 4.00-4.54 log CFU/g, ND-210 MPN/100 g and 110-410 MPN/100 g, respectively. The viable contaminating cell counts on employees, equipment and work areas were in the range of $0.90-3.46log\;CFU/100cm^2$. Airborne bacteria in the work areas ranged from 0.60 to 1.81 log CFU/plate/15 min. Thus, no significant health risks were detected in the processing plant.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.6
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• pp.842-850
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• 2020

The objective of this study was to evaluate the effect of the depuration process (artificial seawater sterilization using UV light) for extending the shelf life of raw oyster Crassostrea gigas and maintaining food quality. To confirm the effects of depuration, microbiological (viable cell count) and several physiochemical analyses (pH and glycogen levels in shucked oyster and pH, soluble protein, and turbidity in filling water) were carried out during the storage of raw oysters. The results showed that depuration could effectively extend the shelf life (2-3 days) of raw oysters with minimal change in food quality, including pH and glycogen content. Thus, the depuration process proposed in this study could successfully be applied to processing practices for other shellfish to extend their shelf life and contribute to the management of seafood safety issues.

• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.4
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• pp.878-883
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• 2008

Conchiolin is a complex protein which is secreted by the mollusc's outer epithelium to be the organic basis of mollusc shell. This study is to investigate a potential anti-inflammatory activity of conchiolin of oyster shell (COS). We tested the effects of COS on the lipopolysaccharide (LPS)-induced production of nitric oxide (NO) and prostaglandin E2 (PGE 2) in a murine macrophage cell line, RAW 264.7. COS inhibited production of NO and PGE2 in a dose dependent manner and also decreased the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis $factor-{\alpha}$ ($TNF-{\alpha}$) and interleukin-6 (IL-6). These results suggest that COS can inhibit production of pro-inflammatory mediators and might be a useful source to treat inflammation.

• Economic and Environmental Geology
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• v.52 no.2
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• pp.119-128
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• 2019

About 300,000 tones of oyster shell are annually produced in Korea and, thus, a massive recycling plan is required. Many desulfurizing studies using oyster shells with chemical composition of $CaCO_3$ have been performed so far; however, most of them have focused on dry desulfurization. This study investigates the possibility of using oyster shells for wet desulfurization after calcination. For this, a simulated wet desulfurization facility of spray type was devised and compared the SOx-stripping characteristics of calcined oyster shell with those of limestone. The calcined oyster shell slurry indicate a better desulfurizability than the slurries of raw shell or limestone because the oyster shell transformed to a more reactive phase ($Ca(OH)_2$) by the calcination and hydration. Because of this reason, when the calcined oyster shell slurries were used, the reaction residue showed the higher gypsum ($CaSO_4{\cdot}2H_2O$) contents than any other cases. In the continuous desulfurization experiments, calcined oyster shell slurry showed a wider pH variation than limestone or raw oyster shell slurries, another clear indication of high reactivity of calcined oyster shells for $SO_2$ absorption. Our study also shows that the efficiency of wet desulfurization can be improved by the use of calcined oyster shells.

• Food Science and Preservation
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• v.9 no.1
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• pp.56-60
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• 2002

Physiological functions of oyster mushroom Kimchi were investigated. Oyster mushroom Kimhies were found to have antioxidant activities. The effect was in a dose-dependent manner, the effect was higher in oyster mushroom Kimchies than in control and higher in raw oyster mushroom Kimchi (ROMK) than in blanched oyster mushroom Kimchi (BOMK). Methanol extract of Kimchi revealed antimutagenic activity and suppressed growth of cancer cell in a dose-dependent manner, and the effects were higher in ROMK than in other Kimchies. The methanol extracts of oyster mushroom Kimchi alone did not appear proliferation effect of spleenic immune cell, but revealed the effect with Con A. The proliferation effect was higher in ROMK than in BOMK.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.9 no.2
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• pp.111-119
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• 1976

Discoloration of canned boiled oyster namely greening, yellowing and browning often occur separately or associatively in the storage of the product. Greening is mainly caused by the appearance of chlorophyll and its derivatives on the surface around the digestive diverticula of the oyster and yellowing by dispersion of carotenoid. Browning reactions by sugar amino condensation or enzymatic action, tyrosinase, also cause an undesirable color development. In this paper, the stability and the changes in distributional or partitional ratio of chlorophyll and carotenoid pigment of meat vs viscera in raw and canned oyster during six month storage in order to measure the dispersion rate of both pigments between meat and viscera, and to evaluate the feasibility of discoloration of oyster meat. The development of brownish pigment and the toss of free tyrosine in oyster were also determined to compare the readiness of color development. In addition the influence of processing and storage conditions to the dispersion rate and the tendency of discoloration, and finally the effect of inhibitor were discussed. The results showed that greening or yellowing was initiated by the dispersion of chlorophyll or carotenoids from viscera to the meat of oyster, and the dispersion rate of carotenoid was much higher than the chlorophyll's, so that, yellowing appeared a leading reaction of discoloration. The dispersion rate was obviously fastened by raising the temperature in the process of sterilization and storage. Consequently, the low temperature storage could largely retard the occurance of yellowing or greening of oyster meat. The pH control of canned oyster did not seem to affect the dispersion of pigment but significantly did on the stability of the piqments. Browning by the reaction of sugar-amino condensation and enzymatic oxidation of tyrosine was positively detected in canned oyster meat. The development of brownish color was influenced rather by the storage temperature than the heating process. Addition of sodium sulfite in can or treating the boiled oyster with sulfite solution prior to filling seemed possibly inhibit the color development particularly in cold-storaged oyster meat.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.2
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• pp.85-93
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• 2006

This study was conducted to evaluate the optimal processing conditions of smoke-dried powdered oysters and to determine their shelf-life during storage for development of a natural oyster flavoring substance. The optimal conditions for processing of smoke-dried oyster powder with freshy oyster were as follows. Raw shelled oysters were rinsed with 3% saline solution, drained, boiled for 10 minutes at $98^{\circ}C$, and then smoked for 1 hour at $50^{\circ}C$, followed by drying for 4 hours at $80^{\circ}C$ Smoke-dried oyster powder with oyster scraps were prepared as flavoring material. The smoked oyster scraps were submerged in oyster sauce far 10 minutes at room temperature and then dried with hot air for 5 hours at $50^{\circ}C$. The smoke-dried oysters and smoke-dried oyster scraps were then pulverized to 50 mesh and packed in tea bags or vacuum-packed in laminated plastic film bags (PE/PVDC/CPP, $12{\mu}m/15{\mu}m/50{\mu}m$). Compared to non smoke-dried powdered oysters, the smoking and dipping in oyster sauce enhanced the flavor and prevented lipid oxidation of the smoke-dried powdered oyster product. Shelf-life tests indicated that the vacuum-packaging method preserved the quality of smoke-dried powdered oysters stored for 150 days at room temperature.

• Animal Bioscience
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• v.35 no.8
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• pp.1279-1288
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• 2022

Objective: The aim of this study was to investigate antioxidant activities of cinnamon (Cinnamomum cassia) extracts (extracted with different solvents) at various concentrations and to determine product quality of raw chicken patties added with different levels of cinnamon powder (CP) and oyster mushroon powder (OMP) during storage. Methods: After cinnamon was made into oven dried CP and extracted with water and different levels (50%, 80%, and 100%) of ethanol, antioxidant activities of these extracts were determined. CP and OMP were combined at different levels and added to raw chicken patties. Physicochemical properties and microbial counts were measured during refrigerated storage. Results: Cinnamon ethanol (80%) extract showed the highest (p<0.05) by 2,2-diphenyl-1picrylhydrazyl-radical scavenging activity and reducing power. Cinnamon water extract (CWE) had the highest iron chelating ability (p<0.05), while CP 100% ethanol extract had the highest content of total phenolic compound. Then, CP and OMP were applied to chicken patties at different levels (0.1% to 0.2%). After the addition of CPs, pH, L* (lightness), 2-thiobarbituric acid reactive substance, and volatile basic nitrogen values were decreased, whereas a* (redness) and b* (yellowness) values were increased. Microbial counts of total bacteria and Enterobacteriaceace were decreased with the addition of CP 0.2% regardless of the OMP level. Conclusion: The addition of CP in combination with OMP can increase the shelf-life of chicken patties during storage.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.3
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• pp.347-353
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• 1995

[ $F_o-value$ ] of canned smoked-oyster in cottonseed oil (SOCO) were measured using a microcomputer aided $F_o-value$ measuring system, and the microbiological safety of the canned SOCO was evaluated to optimize the energy consumption. Most of the microorganisms in raw oyster were saprophytes. No microorganisms were detected from the canned SOCO which was pretreated by conventional procedure and sterilized at $110^{\circ}C$ with $F_o-value$ of 5.92min and over. The most heat resistant microflora isolated from the raw oyster was Bacillus sp.. D-value at $121.1^{\circ}C$ and z-value of spores of Bacillus sp. in the SOCO homogenate were 4.10min and $10,91^{\circ}C$, respectively. After 120 days storage at $50^{\circ}C$, no growth of microorganisms was recognized from the canned SOCO with $F_o-value$of 5.92min.

• Fisheries and Aquatic Sciences
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• v.6 no.4
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• pp.220-224
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• 2003

In order to determined the appropriate processing season of Pacific oyster (Crassostrea gigas), 30 individuals cultured in Kamak Bay on the southern coast of Korea were taken bimonthly 7 times a year, and seasonal variation of edible portion weight, edible portion yield and coefficient of fatness were investigated. There were close relationships between edible portion weight (X) and total weight (Y) and between coefficient of fatness (X) and edible portion yield (Y), which were expressed in regression lines, i.e. Y=0.2709X-1.9094 (r=0.9254) and Y=44.0596X+ 15.1127 (r=0.8485), respectively. From the results of seasonal variation of edible portion weight, yield and coefficient of fatness, the appropriate processing season of raw Pacific oyster was between winter and spring, that is, between December and following April the next year.