• Parasites, Hosts and Diseases
• /
• v.56 no.3
• /
• pp.301-304
• /
• 2018

Rodents are important reservoirs of diseases affecting people and livestock, and are major sources of parasite contamination of agricultural products. We surveyed the infection status of intestinal helminths in 2 species of field mice, Apodemus agrarius and A. peninsulae, captured in the agricultural fields of Gangwon-do and Chungcheongnam-do, Korea. Total 83 mice (57 A. agrarius and 26 A. peninsulae) were collected in 2 surveyed areas, and the intestines of each mouse were opened with scissors, and then intestinal contents were examined with microscope. Total 6 species of intestinal helminth were detected in 61 (73.5%) out of 83 mice examined. Four species of nematode, i.e., Nippostrongylus brasiliensis, Aspiculuris tetraptera, Heterakis spp. and ascarid, were found in 40 (48.2%), 14 (16.9%), 11 (13.3%) and 13 (15.7%) mice respectively. One species of cestode, Hymenolepis diminuta and 1 unidentified egg were also detected in the intestines of 14 (16.9%) and 1 (1.2%) mice, respectively. Conclusively, this study identified 5 helminth species in the gastrointestinal tracts of wild rodents captured in some areas in central and northern Korea, and N. brasiliensis was the most prevalent (dominant) species rather than zoonotic ones.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.29 no.4
• /
• pp.442-451
• /
• 2019

Objectives: The aim of this study was to review the reduction methods for ammonia (NH₃) and hydrogen sulfide (H₂S) exposure in livestock. Methods: By reviewing domestic and international research reports from Korea and China, reducing ammonia and hydrogen sulfide in livestock pens was analyzed in terms of ventilation, deodorant, and feed additives. In addition, exposure limits in Korea and China were examined through a comparison between 'TLV-TWA and STEL under the Industrial Safety and Health Act in Korea' and 'Management Standards for Air of Livestock Pens in China'. Results and Discussion: In order to effectively control hazardous gases and odors in livestock pens, the enhancement of natural ventilation or the addition of ventilation fans at the pollution source are being examined. Deodorants are used as adsorbents or masking deodorants. Additives to feed were zeolite powder, FeSO₄·7H₂O, enzymes, and microbial preparations. Use of feed additives was low-cost and had significant effects compared to other methods. Zeolite was the most commonly used in feed additive in Chinese cases and proved to be low-cost and effective for reducing harmful gases. Enzyme preparations were shown to stimulate the growth of livestock, but were expensive. Conclusions: This study reviewed and examined domestic and international research papers in Korea and China for reducing ammonia and hydrogen sulfide concentrations in livestock pens. More diverse research and the development of feed additives are needed.

• Journal of Biosystems Engineering
• /
• v.42 no.4
• /
• pp.293-300
• /
• 2017

Purpose: This study aims to propose a method for fast geographical origin discrimination between domestic and imported rice using a visible/near-infrared (VNIR) hyperspectral imaging technique. Methods: Hyperspectral reflectance images of South Korean and Chinese rice samples were obtained in the range of 400 nm to 1000 nm. Partial least square discriminant analysis (PLS-DA) models were developed and applied to the acquired images to determine the geographical origin of the rice samples. Results: The optimal pixel dimensions and spectral pretreatment conditions for the hyperspectral images were identified to improve the discrimination accuracy. The results revealed that the highest accuracy was achieved when the hyperspectral image's pixel dimension was $3.0mm{\times}3.0mm$. Furthermore, the geographical origin discrimination models achieved a discrimination accuracy of over 99.99% upon application of a first-order derivative, second-order derivative, maximum normalization, or baseline pretreatment. Conclusions: The results demonstrated that the VNIR hyperspectral imaging technique can be used to discriminate geographical origins of rice.

• Journal of Animal Science and Technology
• /
• v.54 no.3
• /
• pp.191-198
• /
• 2012

The objective of this study was to evaluate the potential use of a dielectric barrier discharge (DBD) plasma system to improve microbial safety of sliced cheese. The atmospheric pressure plasma (APP) effect on visual appearance and a sensory evaluation were also carried out. The number of Escherichia coli inoculated on cheese slices decreased by 0.09, 0.47, 1.16 and 1.47 log cycles with helium (4 liters/min [lpm]) and 0.05, 0.87, 1.89 and 1.98 log cycles with He/$O_2$ mixture (4 lpm/15 standard cubic centimeters per minute), after being treated with plasma for 1, 5, 10, and 15 min, respectively. Significant reductions were also observed in Staphylococcus aureus inoculated onto cheese slices ranging from 0.05 to 0.45 log cycles with He and from 0.08 to 0.91 log cycles with He/$O_2$-treated samples, respectively. Adding oxygen resulted in a significant increase in inactivation of both pathogens. No visible change in the plasma-treated cheese slices was observed even though the instrumental analysis showed a significant decrease in the $L^*$-value and an increase in the $b^*$-value. The cheese slices were damaged after 10 and 15 min of plasma treatment. In addition, significant reductions in sensory quality including flavor, odor, and acceptability of plasma-treated cheese slices were observed. The results indicate that the DBD plasma system has potential for use in sanitizing food products, although the effect was limited. Further development of the APP system is necessary for industrial use.

• Applied Biological Chemistry
• /
• v.49 no.2
• /
• pp.158-162
• /
• 2006

To determine freshness and quality change of tofu during storage, we manufactured a freshness indicator and monitored the surface pH, volatile basic nitrogen (VBN), thiobarbituric acid reacted substance (TBARS), total bacterial counts, and sensory evaluation. Tofu had a change in color of the freshness indicator after storage of 8 days at $4^{\circ}C$, and its pH and total bacterial counts reached 5.6 and 7.63 log CFU/g, respectively. VBN and TBARS values increased and reached the decay point at the time of color change of the freshness indicator. Sensory evaluation also indicated that samples were unacceptable by off-odor and decrease of firmness at day 8 of storage. These results suggest that a freshness indicator should be useful in determining expiration date of tofu products during marketing by indicating the microbial safety as well as sensory change.

• Korean journal of food and cookery science
• /
• v.24 no.4
• /
• pp.445-451
• /
• 2008

This study compared the effects of chlorine dioxide and a commercial chlorine sanitizer for inhibiting foodborne pathogens, including Salmonella enterica serovar Typhimurium, Listeria monocytogenes, and Escherichia coli O157 : H7, on lettuce leaves. The lettuce samples were inoculated with each cocktail of the three strains, and were then treated with chemical sanitizers [distilled water, 100 ppm commercial chlorine and 50 ppm, 100 ppm, 200 ppm chlorine dioxide ($ClO_2$)] for 1 min, 5 min, and 10 min at room temperature($22{\pm}2^{\circ}C$). Following inoculation of the leaves, initial populations of E. coli O157:H7, L. monocytogenes, and S. Typhimurium were approximately 5.54, 4.47, and 5.12 log CFU/g, respectively these levels were not significantly reduced by the treatment with water,whereas the 100 ppm commercial chlorine sanitizer treatment and $ClO_2$ (at all tested concentrations) were effective at reducing levels of all three pathogens. The treatment of 200 ppm $ClO_2$ for 10 min was most effective at inhibiting the three pathogens, and reduction levels of E. coli O157 : H7, L. monocytogenes, and S. Typhimurium were 2.28, 1.95, 1.76 log, respectively. The inhibitory effect of $ClO_2$ increased with increasing treatment concentration of $ClO_2$, but there was no significant difference by the treatment times. When chemically injured cells of E. coli O157 : H7 and L. monocytogenes and S. Typhimurium were examined by SPRAB and selective overlay methods, respectively, it was observed that the commercial chlorine sanitizer generated greater numbers of injured L. monocytogenes than the $ClO_2$ treatment. From the overall results, $ClO_2$ was more effective at inhibiting pathogenic bacteria compared to the commercial chlorine sanitizer therefore, it has potential to be utilized as an alternative sanitizer to increase the microbial safety of fresh produce.

• Food Science of Animal Resources
• /
• v.31 no.2
• /
• pp.200-206
• /
• 2011

Off-flavor and lipid oxidation are possible defects of irradiated bulgogi. This study compared the effects of several physicochemical treatments on microbial safety, volatiles, lipid oxidation, and sensory properties of irradiated beef bulgogi. Samples were separately irradiated with 20 kGy after each treatment such as packaging (aerobic and vacuum), antioxidants (vitamin C + ${\alpha}$-tocopherol (0.0 and 1.0%, w/w)), charcoal teabags (0 and 0.5%), or different temperatures (room temperature, -20, and -70$^{\circ}C$). No bacterial growth was observed (p<0.05) after irradiation of more than 20 kGy during storage at $35^{\circ}C$. Volatiles created by irradiating bulgogi were toluene, heptane, and 1,3-bis(1,1-dimethylethyl)benzene. Irradiation offflavor, lipid oxidation, and deterioration of sensory quality induced by irradiation were effectively reduced (p<0.05) by all physico-chemical treatments tested.

• Korean journal of food and cookery science
• /
• v.33 no.1
• /
• pp.9-19
• /
• 2017

Purpose: This study was conducted to obtain basic data for the quality characteristics of commercial kimchi pastes. Methods: The physicochemical, microbial, and sensory quality characteristics of kimchi paste purchased from 12 companies (KP 1-12) were investigated. Results: Commercial kimchi pastes contained a moisture content of 61.60-82.99%. The pH and titratable acidity of samples were 4.88-5.92 and 0.56-1.58%, respectively, and salinity was on average, 3%. The reducing sugar content was approximately 67.35 mg/mL, and those of KP 8 was higher by approximately 100 mg/mL. American Spice Trade Association (ASTA) value of kimchi pastes varied based on the samples. The commercial kimchi pastes contained capsaicin and dihydrocapsaicin at 1.51-7.84 and, 0.54-2.26 mg/100 g, respectively; sodium and potassium contents were 383.32-1,563.45 mg/100 g and 264.49-571.95 mg/100 g, respectively; and the Na/K ratio was 1.21-5.48. The number of aerobic bacteria and lactic acid bacteria detected from 5.00 to 8.00 log CFU/g. The number of yeast and mold detected from 0.50 to 2.66 log CFU/g. Coliform was detected at approximately 3-4 log CFU/g, whereas Escherichia coli was detected only in KP 3 and KP 7. Overall acceptability of kimchi paste showed a higher score in KP 1. The commercial kimchi pastes showed higher salinity and Na/K ratio and E. coli was detectedin some kimchi paste samples. Conclusion: Therefore, further studies are required to lower the Na/K ratio, for recipe developments, and the standardization of quality and hygiene safety of kimchi paste.

• Korean Journal of Food Science and Technology
• /
• v.29 no.4
• /
• pp.804-807
• /
• 1997

Palatinose is a disaccharide molecule which can substitute sucrose as a sweetening agent. A microbial fermentation technology has been developed to produce palatinose. In order to verify the safety of palatinose products, we have performed 1) bacterial reverse mutation test using Salmonella typhimurium TA1535, TA1537, TA98 and TA100, and 2) in vitro chromosome aberration test using Chinese Hamster Lung (CHL) cell. In bacterial reverse mutation test, both palatinose and palatinose syrup did not induce any significant increase of $His^{+}$ revertants up to 10 mg/plate. In in vitro chromosome aberration test, palatinose and palatinose syrup also did not cause any significant increase of chromosome aberrant cells up to 5 mg/mL. These results suggest that palatinose products have no mutagenic potential in these in vitro mutagenicity tests.

• Journal of Microbiology and Biotechnology
• /
• v.26 no.2
• /
• pp.385-393
• /
• 2016

Pseudomonas syringae pv. actinidiae causes bacterial canker disease in kiwifruit. Owing to the prohibition of agricultural antibiotic use in major kiwifruit-cultivating countries, alternative methods need to be developed to manage this disease. Bacteriophages are viruses that specifically infect target bacteria and have recently been reconsidered as potential biological control agents for bacterial pathogens owing to their specificity in terms of host range. In this study, we isolated bacteriophages against P. syringae pv. actinidiae from soils collected from kiwifruit orchards in Korea and selected seven bacteriophages for further characterization based on restriction enzyme digestion patterns of genomic DNA. Among the studied bacteriophages, two belong to the Myoviridae family and three belong to the Podoviridae family, based on morphology observed by transmission electron microscopy. The host range of the selected bacteriophages was confirmed using 18 strains of P. syringae pv. actinidiae, including the Psa2 and Psa3 groups, and some were also effective against other P. syringae pathovars. Lytic activity of the selected bacteriophages was sustained in vitro until 80 h, and their activity remained stable up to 50℃, at pH 11, and under UV-B light. These results indicate that the isolated bacteriophages are specific to P. syringae species and are resistant to various environmental factors, implying their potential use in control of bacterial canker disease in kiwifruits.