• Applied Biological Chemistry
• /
• v.50 no.2
• /
• pp.121-126
• /
• 2007

Halophyte and shellfish are functional and favorite foods in Korea. This study was conducted to survey the contents of inorganic metals to elucidate seafood hygiene & safety. The average concentrations of heavy metals in the halophyte and shellfish were 1.73, and 1.54 ppb of Cd and 47.37, 25.06ppm of Cu, respectively. Average contents of Hg in halophytes was 0.26 ppb and 50.43 ppb in shellfish. In case of minerals, the average concentrations were 4,475.62, 4,440.54 ppm of Ca, and 3,936.16, 1,227.09 ppm of Fe, 2,145.36, 6.170.60 ppm of P. and 314.53, 162.11 ppm of Zn, respectively. The average values of heavy metals were all below the permissible amounts in food but minerals showed high levels in halophyte and shellfish.

• Journal of Food Hygiene and Safety
• /
• v.11 no.1
• /
• pp.57-70
• /
• 1996

This paper intends to investigate commercial fish and shellfish 25 species (fish 8 species, shellfish 7 species, crustacean 3 species, moluse 4 species and echinodermata) for the distribution of sanitary indicator organisms (total viable counts, coliforms, staphylococci, vibrios, and enterococci) and distributional change of indicator organisms accordion to storage temperature and period. The logarithmic mean of total viable counts for total commercial fish and shellfish 25 species was 5.41$\pm$.026 CFU/g, and in accordance with fish and shellfishes, crustacean 6.76$\pm$0.67 CFU/g, shellfish 5.67$\pm$0.56 CFU/g, echinodermata 5.47$\pm$1.50 CFU/g, fish 5.02$\pm$0.38 CFU/g, and mollusc 5.03$\pm$0.65 CFU/g. The logarithmic mean of enterococci was 2.36$\pm$0.37 CFU/g, and in accordane with fish and shellfish, crustacean 3.44$\pm$2.12 CFU/g, shellfish 3.87$\pm$0.45 CFU/g, echinodermata 3.38$\pm$0.0 CFU/g, fish 2.16$\pm$0.41 CFU/g and mollusc 0.01$\pm$0.0 CFU/g. The logarithmic mean of vibrios was 1.60$\pm$1.59 CFU/g, and in accordance with fish and shellfish, crustacean 4.23$\pm$1.11 CFU/g, shellfish 3.58$\pm$0.90 CFU/g, echinodermata 1.64$\pm$0.34 CFU/g, fish 1.79$\pm$0.67 CFU/g and mollusc 1.07$\pm$0.61 CFU/g. The logarithmic mean of staphylococci was 1.60$\pm$1.59 CFU/g, and in accordance with fish and shellfish, shellfish 0.01$\pm$0.00 CFU/g, echinodermata 3.51$\pm$0.60 CFU/g, fish 1.68$\pm$0.64 CFU/g, crustacean 0.34$\pm$0.33 and mollusc 3.90$\pm$0.11 CFU/g. The logarithmic mean of coliformas was 2.52$\pm$0.32 CFU/g, and in accordance with fish and shellfish, echinodermata 3.58$\pm$1.89 CFU/g was highest, shellfish 3.25$\pm$0.30 CFU/g, crustacean 3.23$\pm$0.49 CFU/g, fish 2.18$\pm$0.63 CFU/g, peeled shellfish 1.80$\pm$0.51 CFU/g and mollusc 1.55$\pm$0.95 CFU/g. As the results of research of the change of the contaminate indicator microflora in working with storage period at 1$0^{\circ}C$, 2$0^{\circ}C$ and 3$0^{\circ}C$, total viable counts was increased without storage temperature and enterococci were decreased slowly at 1$0^{\circ}C$, but increased at 20 and 3$0^{\circ}C$. Vibrios were decreased slowly at 1$0^{\circ}C$, decreased at 2$0^{\circ}C$ and 3$0^{\circ}C$in 2 days after increased rapidly. Staphylococci were increased promptly without storage temperature in 2 days, then the total viable counts were maintained. Coliforms were increased at 1$0^{\circ}C$ by 7 days, then decreased or maintained after 14 days, changed at 2$0^{\circ}C$ in accordance with fish species in 2 days, then returned to the initial total viable count, and decreased rapidly at 3$0^{\circ}C$ on 2 days. By the way, there were no difference among the species.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.43 no.4
• /
• pp.298-306
• /
• 2010

A sanitary survey was conducted to evaluate the water quality and mussel (Mytilus edulis) conditions of two administrative shellfish growing waters: those designated as shellfish growing water for export, and adjacent waters on the east coast of Changseon Island, Namhae, Korea. In all, 1,656 seawater and 166 mussel samples were collected at 46 stations for seawater and five stations for the shellfish from January 2007 to December 2009. Both seawater and mussels were examined for total coliforms and fecal coliforms. The standard plate count and most probable number of Escherichia coli were also determined for the shellfish samples. The range of the geometric means and the estimated 90th percentiles of fecal coliform for seawater samples at each station were <1.8-4.1 MPN/100 mL and <1.8-22.3 MPN/100 mL, respectively. The sanitary conditions for both shellfish growing areas, the designated shellfish growing area and adjacent area in Changseon, met the 'Approved area' criteria of the United States National Shellfish Sanitation Program. The range of E. coli detected in mussels in these areas was <20-500 MPN/100 g; and only 3 of 166 samples exceeded 230 MPN/100 g, the European standard for the consumption of raw bivalves. Therefore, the mussel farms in the Changseon area are classified as 'Class A' according to criteria set in European Community regulations. However, the levels of E. coli in mussels in parts of the designated shellfish growing area and adjacent area exceeded the bacterial limits after rainfall exceeding 45 mm. Further studies are needed to fully define the conditions leading to a temporary closure to harvest after a rainfall event.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.34 no.3
• /
• pp.179-183
• /
• 2001

Shortnecked clam, Ruditapes philippinarum, is one of the very important shellfish produced in south-western coast of Korea. But it's ready to be polluted and have sand in flesh because it mainly inhabit in silt at the inside of coastal area. This study was carried out to obtain informations about the elimination of sand in shortnecked clam harvested from western coast of Korea. During rearing shortnecked clams in water tank, the elimination rates of sand from them at 6, 13, 23, $28^{\circ}C$ were 59.0, 88.2, 97.9, $96.1^{\circ}C$ after 48 hours, respectively. The sand was eliminated above $95^{\circ}C$ from the shellfish at 32,9 to $40\%_{\circ}$ of salinity after 48 hours. But the sand elimination from them was incomplete and inconsistent at 10 to 20 of salinity. The sand was eliminated rapidly at pH 1.9 to 9.0 however, its elimination was not effective at neutral or acidity range, It was found that the sand elimination was most effective at $23^{\circ}C, 35\%_{\circ}$ salinty and pH 9.0. Reasonable flow rate for sand eliminate in shortnecked clam was above 150 L/min./shellfish $m^3$ under both 3,000 and 4,000 L/shellfish $m^3$, and above 100 L/min,/shellfish $m^3$ under both 6,000 and 8,000 L/shellfish $m^3$ in water tank.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.53 no.2
• /
• pp.174-180
• /
• 2020

The mouse bioassay has been used widely for the monitoring of paralytic shellfish toxins (PSTs) in many countries. However, this method shows low sensitivity and high limit of detection (LOD), as well as it cannot confirm toxic profiles. Recently, LC-MS/MS method was studied for the quantitative of PSTs, however, the method has any problems with unstable retention times by ionization suppression caused by high salt concentration in shellfish extracts. To establish an alternative method for PSTs analysis, we tried to original LC-MS/MS methods adding desalting operation using amorphous graphitized polymer carbon solid-phase extraction cartridges. The method validation was conducted to determine linearity, limit of detection, limit of quantification (LOQ), accuracy, and precision in quantifying PSTs. The correlation coefficients for all tested PSTs maintained over 0.999. The LODs and LOQs for all PSTs were about 0.19-1.05 ㎍/kg and 0.58-3.18 ㎍/kg, respectively. The accuracies for PSTs were 95.4-107.7% for saxitoxin group, 97.1-100.9% for gonyautoxin group, 99.0-100.8% for N-sulfocarbamoyl toxin group, and 96.8-104.6% for decarbamoyl toxin group. These results indicate that the modified LC-MS/MS method was appropriate for analyzing the PSTs in shellfish and tunicates.

• Fisheries and Aquatic Sciences
• /
• v.11 no.1
• /
• pp.7-14
• /
• 2008

The sanitary quality of a shellfish-growing area in Kamak Bay, Korea, was assessed through a bacteriological examination of seawater and oysters from January 2004 to December 2006. From seawater samples collected at 28 stations, the range of geometric mean (GM) and the estimated 90th percentile for most-probable-number (MPN) values of fecal coliforms were <1.8-2.4 MPN/100 mL and 1.8-6.0 MPN/100 mL, respectively. The observed fecal coliform GM and the estimated 90th percentile did not exceed the fecal coliform water quality standards of 14 MPN/100 mL and 43 MPN/100 mL. Therefore, the bacteriological quality of seawater at this shellfish-growing area met the Korean Shellfish Sanitation Program (KSSP) criteria for a growing area used for export. The range of the fecal coliform GM and the estimated 90th percentile MPN values of oyster samples were 19.2-160 MPN/100 g and 20.2-166.9 MPN/100 g, respectively, and the range of the viable cell count was 30-1900 CFU/g. Thus, the fecal coliform value for the oysters and the viable cell count were less than the current shellfish quality standards of 230 MPN/100 g and 50,000 CFU/g, respectively. The bacteriological quality of the oysters complied with the criteria for domestic use and export of shellfish.

• Journal of Environmental Science International
• /
• v.17 no.8
• /
• pp.841-856
• /
• 2008

This research outlines a new method for evaluation of shellfish production in Gamak Bay based on the concept of EMERGY. Better understanding of those environmental factors influencing oyster production and the management of oyster stocks requires the ability to assess the real value of environmental sources such as solar energy, river, tide, wave, wind, and other physical mechanisms. In this research, EMERGY flows from environment sources were 76% for shellfish aquaculture in Gamak Bay. EMERGY yield ratio, Environmental Loading Ratio, and Sustainability Index were 4.26, 0.31 and 13.89, respectively. Using the Emergy evaluation data, the predicted maximum shellfish aquaculture production in Gamak Bay and the FDA (Food and Drug Administration, U.S.) designated area in Gamak Bay were 10,845 ton/y and 7,548 ton/yr, respectively. Since the predicted shellfish production was approximately 1.3 times more than produced shellfish production in 2005, the carrying capacity of Gamak Bay is estimated to be 1.3 times more than the present oyster production.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.51 no.2
• /
• pp.121-126
• /
• 2018

The purpose of this study was to assess bacteriological hazards in the following 7 kinds of minimally processed shellfish products purchased from Korean seafood retail outlets: raw oysters stored with seawater in polyethylene bags, frozen oysters, raw mussels, frozen mussels, boiled mussels, raw short-necked clam, and frozen short-necked clams, obtained from Korean seafood retail outlets. The total coliform and Escherichia coli counts determined in all samples were detected below regulation limit of the Korean government guidelines (Food Code). In addition, the high-risk bacterial pathogens, Listeria monocytogenes, Salmonella spp., and E. coli O157:H7 were not detected in any samples. Low-risk pathogens such as Staphylococcus aureus and Vibrio parahaemolyticus were detected at levels above $1.0{\times}10^2$ colony forming unit (CFU)/g in some minimally processed shellfish products. Notably, S. aureus was detected in all samples. Raw oysters stored with seawater in polyethylene bags, frozen oysters, and boiled blue mussels are commonly ingested without heating, and therefore these minimally processed shellfish products pose bacteriological hazards. The detection of S. aureus in all shellfish products, an organism indicative of poor personal hygiene, which can grow and multiply during distribution, indicates the necessity of improving the food safety of minimally processed shellfish products.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.50 no.4
• /
• pp.352-358
• /
• 2017

The object of this study is to assess physicochemical and microbiological hazards involved during the processing of shellfish products such as oysters, clam, and mussels. Samples including raw materials, intermediates, and final products in the processing process were collected from seven simple-processed shellfish facilities. In the samples obtained from the facilities, viable cell count and coliform group were detected less than that of the Korean Government guidelines. In addition, the high-risk bacterial pathogens such as Escherichia coli O157:H7, Salmonella sp., and Listeria monocytogenes were not identified in raw materials and final products. However, the low-risk pathogens, Staphylococcus aureus and Vibrio parahaemolyticus, were detected in some final products. The level of heavy metal content in the final products tested in this study meets the recommendations by the Korean Government standard guidelines. No foreign materials in the final products were also observed. Considering these results, it was concluded that no significant food hazards exists in the processing process of simple-processed shellfish products. However, it is essential to improve the food safety control in the shellfish processing facilities since S. aureus, a personal sanitary indicative bacterium, was continuously detected over seven simple-processed shellfish facilities.

• Journal of Environmental Science International
• /
• v.29 no.3
• /
• pp.273-282
• /
• 2020

Residence time is defined as the time taken for a material in a system to leave the system. The residence time characteristics in shellfish aquaculture determine the dispersion of excretion from aquaculture farms, along with the supply of food by seawater exchange. In this study, we estimated the spatial distribution of average residence time in the shellfish farming area using a particle tracking model. As a result, a relatively short average residence time of about 20 days or less was calculated in most areas, but an average residence time of more than 40 days was calculated in the inner areas. Relatively long average residence times were calculated along the west coast compared to the east coast, with the longest average residence time of more than 50 days in the northwestern areas. It can be inferred that the disturbance of the benthic ecosystem caused by shellfish farms is likely to be large because of the relatively weak dispersion of excrement from shellfish farms located on the west coast, especially in the northwest region. This distribution of average residence time is important for understanding the potential effects of seawater exchange on the environmental sustainability of shellfish farms, along with the seawater circulation characteristics of Jaran Bay.