Hyunju Choi

Hazardous Metal Pollution in the Republic of Fiji and the Need to Elicit Human Exposure

The fact that hazardous metals do not bio-degrade or bio-deteriorate translates to long-lasting environmental effects. In the context of evidently rapid global industrialization, this ought to warrant serious caution, particularly in developing countries. In the Republic of Fiji, a developing country in the South Pacific, several different environmental studies over the past 20 years have shown levels of lead, copper, zinc and iron in sediments of the Suva Harbor to be 6.2, 3.9, 3.3 and 2.1 times more than the accepted background reference levels, respectively. High levels of mercury have also been reported in lagoon shellfish. These data inevitably warrant thorough assessment of the waste practices of industries located upstream from the estuaries, but in addition, an exposure and health impact assessment has never been conducted. Relevant government departments are duty-bound, at least to the general public that reside in and consume seafood from the vicinities of the Suva Harbor, to investigate possible human effects of the elevated hazardous metal concentrations found consistently in 20 years of surface sediment analysis. Furthermore, pollution of the intermediate food web with hazardous metals should be investigated, regardless of whether human effects are eventually confirmed present or not.

Bactericidal Efficacy of Fumagari OPP ® , Fumigant Against Escherichia coli and Salmonella typhimurium

This test was performed to evaluate the bactericidal efficacy of Fumagari OPP, fumigation disinfectant, containing 20% ortho-phenylphenol against Escherichia coli (E. coli) and Salmonella typhimurium (S. typhimurium). In preliminary tests, both E. coli and S. typhimurium working culture suspension number (N value) was CFU/mL. And all of the colony numbers on the carriers exposed the fumigant (n1, n2, n3) were higher than 0.5N1 (the number of bacterial test suspentions by pour plate method), 0.5N2 (the number of bacterial test suspentions by filter membrane method) and 0.5N1, respectively. In addition, the mean number of bacteria recovered on the control-carriers (T value) was CFU/mL. In the bactericidal effect of the fumigant, the reduction number of S. typhimurium and E. coli (d value) was 5.26 and 5.64 logCFU/mL, respectively. According to the French standard for the fumigant, the d value for the effective bactericidal fumigant should be over than 5 logCFU/mL. With the results of this study, Fumagari OPP has an effective bactericidal activity, then the fumigant can be applied to disinfect food materials and kitchen appliances contaminated with pathogenic bacteria.

Bactericidal Efficacy of Fumagari OPP ® , Fumigant Against Staphylococcus aureus

This study was performed to evaluate the bactericidal efficacy of Fumagari OPP ® , fumigation dis- infectant, containing 20% ortho-phenylphenol against Staphylococcus aureus (S. aureus). In this research, efficacy test of fumigant against S. aureus was carried out according to French standard NF T 72-281. S. aureus working cul- ture suspension number (N value), all of the colony numbers on the carriers exposed with the fumigant (n1, n2, and n3), the number of bacterial test suspentions by pour plate method (N1), the number of bacterial test suspentions by filter membrane method (N2) and the mean number of bacteria recovered on the control-carriers (T value) were obtained from the preliminary test. In addition, the reduction number of S. aureus exposed with the fumigant (d value) was calculated using T value, the mean number of bacteria in recovery solution (n1) and the mean number of bacteria on carriers plated in agar (n2). N value was 4.0 × 10 8 CFU/mL, and n1, n2, and n3 were higher than 0.5N1, 0.5N2 and 0.5N1, respectively. Additionally, T value was 3.4 × 10 6 CFU/mL. In the bactericidal effect of the fumigant, the d value was 6.43 logCFU/mL. According to the French standard for the fumigant, the d value for the effective bacteri- cidal fumigant should be over than 5 logCFU/mL. The results indicated that Fumagari OPP ® had an effective bacteri- cidal activity against S. aureus, then the fumigant can be applied to disinfect food materials and kitchen appliances contaminated with pathogenic bacteria.

Application of a Lateral Flow Immunoassay to Determine Ampicillin Residues in Muscle Tissue of Olive Flounder (Paralichthys olivaceus)

Antibiotic Detection Kit (Combination I), a lateral flow immunoassay (LFIA) developed for the detection of antibiotic residues in milk, was utilized for the analysis of antibiotic residues in the muscle tissue of olive flounder. After 60-min treatment by dipping in water dosed with ampicillin (200-g/ton water), the residue depletion of ampicillin was investigated in 25 cultured olive flounder (Paralichthys olivaceus). Muscles of fish were sampled on the 1st, 2nd, 3rd, 4th and 5th day after drug treatment. The concentration of ampicillin in the muscle was determined by LFIA. The absorbance ratio of the sample to the control blank (Bs/Bo) was employed as an index to determine the muscle residues in olive flounder. To investigate the recovery rate, standard solutions were added to muscle samples to give final concentrations in the muscle of 4 and 8 ng/ml. The recovery rates of all spiked samples were > 96% of the spiked value. Ampicillin was detected in the muscle of fish treated with the drug until the 2nd day of the with- drawal period. The present study showed that the LFIA can be easily adopted to predict ampicillin residues in tissue of farmed fishes.

Antiviral Efficacy of an Aquatic Disinfectant Tablet Composed of Calcium Hypochlorite Against Viral Hemorrhagic Septicemia Virus

Objectives: The objectives of this study were to identify the virucidal efficacy against the viral hemorrhagic septicemia virus (VHSV) of an aquatic disinfectant tablet composed of calcium hypochlorite. Methods: Virucidal efficacy was determined through the viability of VHSV contacted with the disinfectant in a viral stock cultured in a fathead minnow cell line. An aquatic disinfectant tablet and VHSV were reacted under distilled water (DW), hard water (HW) or organic matter suspension (OM) conditions. Results: Under DW and HW conditions, VHSV was inactivated with 24,000- and 2000-fold dilutions of the aquatic disinfectant tablet, respectively. With the investigation of the antiviral effect of the disinfectant under OM conditions, VHSV was inactivated with a 16,000-fold dilution of the aquatic disinfectant tablet. Conclusions: The results from this study showed that the aquatic disinfectant tablet was a highly effective disinfectant against VHSV. In the future, a controlled field trial is required to determine whether the use of an aquatic disinfectant tablet will be able to reduce VHSV in a cultured marine fish farm.

Antimicrobial Activity of Sodium chlorate and Korean Herbal Extracts against Mice infected with Escherichia coli O157:H7

ABSTRACT - The present study was evaluated the antibacterial effect of the combination of Coptidis rhizoma,Glycyrrhiza uralensis Fischet, Schizandra chinensis and Corni Fructus(1:1:1) extracts(CGSC10). Furthermore, theeffectiveness of CGSC10, sodium chlorate, and the combination of CGSC10 and sodium chlorate(CGSCS10) againstE. coli O157:H7 infection was studied using ICR female mice. During the incubation period, the dose of 5, 10, and20% CGSC10 was inhibited the growth of E. coli O157:H7 by 34.7, 60.2, and 76.4%, respectively. For 7 days aftersingle challenge with E. coli O157:H7, forty female ICR mice were divided into four experimental groups which wereadministered in drinking water with saline, 10% CGSC10, 15 mM sodium chlorate, and CGSCS10, respectively. Onthe 3rd day, the number of E. coli O157:H7 in mouse feces was significantly decreased by administration of CGSC10,15 mM sodium chlorate, and CGSCS10 (p < 0.001). On the 7th day-after administration, CGSC10, sodium chlorate,and CGSCS10 were decreased the number of E. coli O157:H7 by 27.1, 67.7, and 83.3%, respectively. According tothe results of the present study, administration of CGSCS10 to mice can reduce the severity of E. coli O157:H7 infec-tion. In addition, it is suggested that CGSCS10 represents a good candidate for the treatment of enteric infections indomestic animals. Key words: Korean traditional herbal extracts, sodium chlorate, antibacterial activity, E. coli O157:H7

Effects of short-term sodium chlorate exposure on pigs

The present study evaluated the effects of exposure to different doses of sodium chlorate in 10-week-old pigs. Twenty pigs were divided into four equal groups and treated with different doses of sodium chlorate: 0, 125, 250 and 500 mg kg-1 body weight per day via the drinking water for 7 consecutive days. The results showed a significant decrease (P < 0.05) in red blood cell and white blood cell counts, packed cell volume, haemoglobin, blood urea nitrogen (P < 0.001) and creatinine levels, and an increase in aspartate aminotransferase and alanine aminotransferase (P < 0.05) activities in swine administered sodium chlorate at a dose of 500 mg kg-1 body weight per day. The histopathological study revealed increased numbers of vacuoles in the convoluted tubules, tubular necrosis and degeneration of the renal tubular epithelial cells, depletion of nuclei and lobular necrosis of the liver in all pigs treated with sodium chlorate at 500 mg kg-1 body weight per day. Thus, 7-day administration of sodium chlorate at 500 mg kg-1 body weight per day to pigs affects the liver and kidney tissues as well as the haematologic and serum biochemical parameters.

Bactericidal Efficacies of an Aquatic Disinfectant Tablet Composed to Calcium Hypochlorite Against Vibrio anguillarum and Streptococcus iniae

Vibrio spp. and Streptococcus spp. have caused a considerable disease of farmed fish and economic loss in fish farming and seafood industry. In this study, the efficacy of an aquatic disinfectant tablet composed to cal- cium hypochlorite was evaluated against V. anguillarum and S. iniae. A bactericidal efficacy test by broth dilution method was used to determine the lowest effective dilution of the disinfectant following exposure to test bacteria for 30 min at 4 o C. An aquatic disinfectant tablet and test bacteria were diluted with distilled water (DW), hard water (HW) or organic matter suspension (OM) according to treatment condition. V. anguillarum on the DW, HW and OM condi- tion was completely inactivated with 16,000 15,000 and 13,000 fold dilutions of the disinfectant, respectively. On the DW, HW and OM condition, S. iniae was absolutely inactivated with 17,000 16,000 and 14,000 fold dilutions of the disinfectant, respectively. As an aquatic disinfectant tablet possesses bactericidal efficacy against fish pathogenic bac- teria such as V. anguillarum and S. iniae this disinfectant solution can be used to control the spread of fish infective bacterial diseases.

Therapeutic Effect of Dioctahedral Smectite on Diarrhea Caused by E. coli and Salmonella in Calves

The objectives in the present study were to evaluate the therapeutic effect of dioctahedral smectite(smectite) against calf diarrhea caused by pathogenic E. coli and/or Salmonella typhimurium. Of this study, twenty calves (aged 2-3 months) with diarrhea were used to estimate the efficacy of smectite on calf diarrhea with 20% smectite suspension in PBS. Calves were administered with 10 ml smectite suspension three times a day after feeding, and fecal samples were collected at the gate of treatment and on 1st, 2nd, 3rd, 4th, and 5th day after administration. On the 5th day after treatment of smectite suspension, the treated group significantly reduced diarrhea index compared to control group (P<0.001). The number of pathogenic E. coli in feces of the treated group was significantly decreased compared to each control group from on the 2nd day after treatment (P<0.001), and that of Salmonella typhimurium was significantly decreased from on the first day after treatment (P<0.05). From results of the present study, 20% smectite suspension had therapeutic effect on diarrhea caused by E. coli and/or Salmonella in calves.