• Journal of fish pathology
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• v.37 no.1
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• pp.133-138
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• 2024

This study is a report on combinational effects between four sesquiterpene lactones (SLs) from bay laurel (Laurus nobilis) leaves, and oxytetracycline (OTC) or amoxicillin (AMX) against four fish pathogenic bacteria such as Vibrio anguillarum, V. harveyi, Edwardsiella tarda, and Streptococcus iniae. Individually, four SLs exerted little antibacterial activity against fish pathogenic bacteria. However, when combined with OTC or AMX, they showed synergistic interaction against pathogenic bacteria. Especailly, zaluzanin C (1) reduced the MIC of OTC (or AMX) eight-fold. Our results showed that combinations of SLs with antibiotics (ABTs) are more effective than ABTs alone to control pathogenic bacteria. The highest synergistic effect was observed when zaluzanin C (1) was combined with OTC or AMX against V. harvey or S. iniae, displaying significant reductions of MICs up to 8-fold (0.125 to 0.015 ㎍/mL and 0.0078 to 0.0009 ㎍/mL). In addition, zaluzanin C (1) improved the antibiotic potency of OTC against OTC resistant V. harveyi (250 ㎍/mL to 62.5 ㎍/mL). Synergism between ABTs and phytochemical such as SLs could be a therapeutically helpful concept to improve the efficacy of ABTs and prevent antibiotic resistance. These results suggest that SLs can be used as an alternative to reduce antibiotic resistance in aquaculture.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.1
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• pp.15-22
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• 2024

This study assessed microbial contamination in seven fried fish pastes sold in Southeast Asian traditional markets during summer. It measured viable cell count, coliforms, Escherichia coli, fungi, and Staphylococcus spp. It also qualitatively analyzed Vibrio parahaemolyticus, Salmonella spp., Bacillus cereus, Listeria monocytogenes, and Clostridium perfringens. The average viable cell count, coliforms and fungi were detected as 6.34 (3.84-8.13), 2.16 (1.00-3.55), and 3.92 (1.85-7.74) log₁₀ CFU/g, respectively. Staphylococcus spp. was detected at 4.59 (2.10-7.63) log₁₀ CFU/g. Some samples had high contamination levels: viable cell count (8.13 log₁₀ CFU/g), fungi (7.74 log₁₀ CFU/g) and S. aureus (7.63 log₁₀ CFU/g). However, E. coli was not detected in any samples (ND, <1 log₁₀ CFU/g). V. parahaemolyticus, Salmonella spp., B. cereus, L. monocytogenes, and Cl. perfringens were also not detected in the samples. The microbial contamination data provide insight into managing microbial contamination and ensuring the safety of fried fish pastes in traditional summer markets.

• Food Science of Animal Resources
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• v.44 no.4
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• pp.805-816
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• 2024

The aim of this study was to evaluate a new Bacillus amyloliquefaciens B-1895 probiotic as a feed additive for farmed trout. Final weight, absolute and average daily gain of fish, and average daily growth rate were higher in the group that received the probiotic than in the control group (p<0.05). Moreover, the probiotic-fed trout had more intense growth rates than the control group (higher by 15.7%; p<0.05). A decrease in feed ratio was also observed in the group that received probiotic (25% decrease; p<0.05), indicating more efficient digestion and assimilation of feed. In general, the introduction of probiotic in the feed did not adversely affect the functional status of the fish. In young trout of the control group, when assessing the general chemical composition of the organism in the muscle tissue revealed significantly (p≤0.001) higher level of moisture content by 5.1% and lower by 11.0% dry matter content. In muscle, the protein content was higher by 1.33% (p≤0.001) and fat content by 2.1% (p≤0.001) in experimental fish. Generally, Lactobacilli, Enterococcus, Vibrio, Bacillus, and coliform bacteria were found in the intestinal samples of rainbow trout. Significant reliable difference (p≤0.05) between the samples of experimental and control groups was noted in the content of Bacillus bacteria. In the control group, 5.0±0.4×10³ CFU/g was detected, while in the experimental group 8.4±0.8×10⁴ CFU/g. Overall, the data indicate that probiotic bacteria B. amyloliquefaciens B-1895 has no adverse effect on selected microorganisms in the study fish.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.3
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• pp.203-208
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• 2024

Fifteen cultured frozen abalone Haliotis discus hannai samples were purchased from supermarkets, traditional markets, online markets, and processing factories throughout Korea for the safety assessment of microbiological and chemical hazards. Sanitary-indicative (total viable bacteria, coliforms, and Escherichia coli) and pathogenic (Staphylococcus aureus, Salmonella spp., Listeria monocytogenes, Vibrio parahaemolyticus, Clostridium perfringens, and Enterohemorrhagic E. coli) bacterial contamination levels were assessed quantitatively or qualitatively. Additionally, heavy metal content (lead, cadmium, and total mercury) and radioactivity (¹³⁴CS+¹³⁷CS, ¹³¹I) were quantitatively assessed. The total viable bacterial count was 4.3×10² CFU/g, while coliform count was 50 CFU/g. E. coli was not detected in any of the samples (count < 10 CFU/g). All six pathogenic bacteria tested negative qualitatively. The average lead, cadmium, and total mercury contamination levels in the cultured frozen abalone were 0.100±0.057, 0.145±0.061, and 0.015±0.001 mg/kg, respectively. Moreover, none of the samples were radioactive. According to the results of this study, cultured frozen abalones distributed in all types of markets were safe from all microbiological and chemical hazards.

• Journal of Species Research
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• v.13 no.3
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• pp.318-325
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• 2024

Bacterial communities residing on islands have a significant impact on the functioning and establishment of a unique isolated ecosystem. Notwithstanding, systematic research on the indigenous microbial resources of domestic islands has been lacking. In order to understand the biodiversity and potential bioresources, we conducted sampling in 2023 from coastal waters from various islands off the west coast of the Korean Peninsula, including Baengnyeongdo, Daebudo, Deokjeokdo, Jangbongdo, Yeonpyeongdo Islands, along with Somaemuldo Island along the south coast. The coastal seawater samples were used to unearth microbial resources through the standard dilution plating. In total, approximately 1,600 bacterial strains were isolated from the samples as single colonies and identified using 16S rRNA gene sequence analyses. Eighteen strains, exhibiting ≥98.7% 16S rRNA gene sequence similarity to bacterial species with validly published names but not previously reported in Korea, were categorized as unrecorded bacterial species in Korea. These unrecorded bacterial strains displayed phylogenetic diversity, representing three phyla, four classes, 9 orders, 13 families, and 18 genera. The unrecorded species were assigned to the classes Alphaproteobacteria (Aliiroseovarius, Kiloniella, Maritalea, Palleronia, and Roseobacter), Gammaproteobacteria (Aliamphritea, Aliivibrio, Enterovibrio, Francisella, Leucothrix, Pseudoalteromonas, Psychrobium, Shewanella, and Vibrio), Flavobacteriia (Aquimarina, Pseudofulvibacter, and Tenacibaculum), and Verrucomicrobiae (Roseibacillus). This study presents comprehensive descriptions of the taxonomic attributes of these unrecorded species, covering morphology, biochemistry, and phylogenetic position.

• Journal of agricultural medicine and community health
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• v.30 no.2
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• pp.137-149
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• 2005

Objectives and Methods: This study was performed to investigate the etiologic bacterial, viral and protozoal organisms for the diarrhea from hospitals in Chungnam area from January to December in 2004. Total of 787 fecal samples were collected and examined. Results and Conclusions: In test for enteropathogenic bacteria, total of 79 cases out of 787 samples from hospitals showed positive isolation. Among 79 positive samples, 27 cases were confirmed as Salmonella spp.. 20 cases as pathogenic E. coli, 18 cases as Clostridium perfringens, 6 cases as Staphylococcus aureus, 4 cases as Shigella spp. and 4 cases as Vibrio parahaemolyticus. In test for enteropathogenic virus, 190 cases out of 787 samples from hospitals showed positive reaction. Among 190 samples, 115 cases were confirmed as rotavirus, 55 cases as norovirus, 5 case as astrovirus, 4 case as rotavirus & norovirus, 3 cases as adenovirus, 2 case as rotavirus & astrovirus. In test for enteropathogenic protozoa, 6 cases out of 787 samples from hospitals showed positive result. Among 6 samples, 5 cases were confirmed as Entamoeba histolytica and 1 cases as Giardia lamblia. When we classified the positive results by the age of the patients, the highest isolation rate was noted in a group of age under 10 and over 60 for bacterial, viral and protozoal pathogens. Especially, patient below age of 5 showed high positive rate. When we classified the positive results by the time, pageathogenic bacteria were isolated throughout the year, and the highest frequency was noted in August. On the other hand, pathogenic viruses were detected more frequently during the colder season from December to April. Antimicrobial susceptibility test for the isolated bacteria resulted as follows; Salmonella strains showed high drug resistance rates against ampicillin, chloramphenicol, tetracycline, nalidixic acid, ticarcillin. Shigella strains showed high drug resistance rates against ampicillin, trimethoprim/sulfamethoxazole, chloramphenicol, tetracycline, ampicillin/sulbactam, ticarcillin. Pathogenic E. coli strains showed high drug resistance rates against ampicillin, cephalothin, gentamicin, tetracycline, nalidixic acid, ampicillin/sulbactam, ticarcillin.

• Korean Journal of Food Science and Technology
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• v.43 no.1
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• pp.91-97
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• 2011

This study was performed to assess the microbiological quality and potential health risk of fresh-cut produce and organic vegetables sampled from supermarkets and department stores in Korea. A total of 96 samples comprised three types of fresh-cut produce (sprouts, mixed-vegetables, fruit) and three types of organic vegetables (lettuce, perilla leaf, green pepper). The samples were analyzed for total viable cell counts, coliforms, Enterobacteriaceae, Escherichia coli, Salmonella spp., Listeria monocytogenes, Vibrio parahaemolyticus, Bacillus cereus, and Staphylococcus aureus. The microbiological counts of fruit were very low. Sprouts were highly contaminated by total viable cell counts ($8.3{\pm}0.57$ log CFU/g), Enterobacteriaceae ($7.1{\pm}0.76$ log CFU/g), and coliforms ($4.9{\pm}0.40$ log MPN/g), and showed a high incidence level of B. cereus ($2.9{\pm}0.48$ log CFU/g). Of the fresh-cut produce analyzed, six (13.6%) mixed-vegetable salads were E. coli positive. S. aureus was detected in only one sprout sample and one mixed-vegetable salad, and its contamination levels were under 2 log CFU/g, which is appropriate for Korean standards (<3 log CFU/g) of fresh-cut produce. Of the organic vegetables, lettuces were highly contaminated by total viable cell counts ($6.4{\pm}0.74$ log CFU/g), Enterobacteriaceae ($5.7{\pm}0.98$ log CFU/g), and coliforms ($3.7{\pm}1.72$ log MPN/g). Two (13.6%) organic lettuce and one (7.1%) perillar leaf sample were E. coli positive, and S. aureus was detected in one lettuce and two perilla leaf samples. Salmonella spp., Vibrio parahaemolyticus, and Listeria monocytogenes were not detected in any of the fresh-cut produce or organic vegetables analyzed.

• Journal of Food Hygiene and Safety
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• v.16 no.4
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• pp.280-294
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• 2001

Despite to the reality that the outbreaks from flood poisoning in Korea have been continuously increasing in the last two decades, it was very much neglected even in the public health field in Korea. Food poisoning outbreaks resulted in many cases not only in the damage of health but also in the death of many lives. However, this problem can be effectively solved by effects through health education activities, but not solely by the legal measures. This study was carried out to provide information that can be used in planning health education programs and proposing new rules to prevent any possible outbreaks from flood poisoning. The main problems contributing to flood poisoning outbreaks in an institutional setting or school catering and at home were reviewed and analyzed through the epidemiological investigations and articles related to flood poisoning in the last a decade (1991 ∼ 2000). Accordingly, the data presented in this study are sufficient to show and prove the significant trends in food poisoning accidents in Korea. The major findings investigated in this study are as follows. The frequency of food poisoning accidents as well as the number of victims have continuously increased in Korea. The number of victims per food poisoning accident is also increased from 20 persons in 1990 to 69.8 persons in 2000. Therefore, we should realize that the group poisoning outbreaks occur more frequently and the size of group poisoning accidents is getting larger. Among four seasons, the food poisoning accidents occurred more frequently in the summer (May ∼September) until 1997, However, after 1997, the food poisoning accidents occurred evenly in three seasons except the winter. The most important bacteria that cause food poisoning in Korea were Salmonella spp., Vibrio spp. and Staphylococcus aureus. They occupied 85∼90% of the rates of accidents and the number of victims.

• Journal of Food Hygiene and Safety
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• v.21 no.1
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• pp.41-46
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• 2006

This study was carried out to survey the prevalence of foodborne pathogens in Sangshik products and their raw materials far the purpose of ensuring safety of those products in market, and establishing microbial regulatory standard. From 2002 to 2004, a total of 191 Sangshik products were purchased from market or mail-order sales, and major foodborne pathogens; E. coli, Salmonella, Staphylococcus aureus, Bacillus cereus, Clostridium perfringens, Listeria monocytogenes, Campylobacter jejuni, Yersinia enterocolitica, E. coli O157:H7, Vibrio parahaemolyticus were tested. B. cereus, C. perfringens and E. coli were detected from 29 samples (15.2%), 21 samples (11.0%) and 1 sample (0.5%), respectively. But other tested bacteria were not detected. For the identification of contamination source, 53 Sangshik ingredients were collected from 9 different manufacture factories. The results were similar with the Sangshik products. Aerobic plate counts were ranging from $1.0X10^3cfu/g\;to\;1.5X10^8cfu/g$. B. cereus was detected from 13 samples (24.5%), and counted as less than 100 cfu/g. C. perfringens were detected from 2 samples (3.8%), and counted as less than 100 cfu/g. Other foodborne pathogens were not detected except for B. cereus and C. perfringens. From the results, it was revealed that potential of microbial hazard by Sangshik was relatively low. However, it would be suggested that hygienic management and controling be needed for the prevention of growing contaminated pathogens and cross contamination during process and sale due to improper storage and management.

• Korean Journal of Food Science and Technology
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• v.33 no.4
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• pp.401-408
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• 2001

The ethanol extract and n-hexane fraction of Commiphora molmol Engl. showed minimum inhibitory concentration of 50 ppm and 25 ppm, respectively, on 5 strains of Listeria monocytogenes at $32^{\circ}C$. The purified substance, C3-3-2 fraction, was isolated by silica gel column and preparative thin layer chromatography from n-hexane fraction of Commiphora molmol Engl. The C3-3-2 fraction showed a strong bactericidal activity on 5 strains of L. monocytogenes at the concentration of 10 ppm in tryptic soy broth medium. At that concentration, the viable count was reduced $5{\sim}6$ log cycle from initial cell number. The n-hexane fraction of Commiphora molmol Engl. showed strong growth inhibition at the concentration of 25 ppm on Bacillus cereus and Staphylococcus aureus, at 50 ppm in broth on Salmonella enteritidis, and at 500 ppm on Vibrio parahaemolyticus. The purified antimicrobial substance, the C3-3-2 fraction, was identified as m-nonylphenol by on the basis of the $^1H-,\;^{13}C-NMR$ and EI/MS data. For the application test, the C3-3-2 fraction which was purely isolated from Commiphora molmol Engl. at 100 ppm were applied to minced Alaska pollack and ground beef at $32^{\circ}C$ and $5^{\circ}C$. The antimicrobial substances did not reduce L. monocytogenes ATCC 19113 at $32^{\circ}C$, while they reduced L. monocytogenes ATCC 19113 in viable number at $5^{\circ}C$. However, the antimicrobial effect of C3-3-2 fraction in food system was lower than that of broth condition.