• Journal of Food Hygiene and Safety
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• v.25 no.2
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• pp.153-161
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• 2010

The purpose of this study was to examine the appearance of norovirus in the water for food in food service institutions and the influence of physicochemical and microbial factors of norovirus in order to work out basic data to predict the detection of norovirus. Among 82 samples of water for food in food service institutions, norovirus appeared in 7 samples and the rate of appearance was 8.5%. As for the type of norovirus, one samples contained GI type (genotype GI-6) and six samples contained GII type (genotype GII-2, GII-4, GII-12). In the regression model of prediction of norovirus, the rate of appearance was correlated with $NH_3$-N, total solids and the consumption of $KMnO_4$, out of such variables as $NH_3$-N, total solids, the consumption of $KMnO_4$, depth, chloride and total colony counts, and its contribution rate for effectiveness was 78.60%. In order to examine the influential factor of environment upon the detection of norovirus, Pearson's correlation analysis was carried out. The predictable regression formula for appearance rate of norovirus was expressed as -1.818 + 42.677 [$NH_3$-N] + 0.023 [total solids] + 0.762 [consumption of $KMnO_4$] -0.009 [depth] -0.146 [chloride] + 0.007 [total colony counts] (R = 0.904, $R^2$ = 0.818, adjusted $R^2$ = 0.786, p < 0.05). The most influential factors upon the detection of norovirus were $NH_3$-N, total solids and the consumption of $KMnO_4$. In other words, when the measured values of $NH_3$-N, total solids and the consumption of $KMnO_4$ were higher, the possibility of appearance of norovirus increased.

• Food Science of Animal Resources
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• v.23 no.3
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• pp.269-277
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• 2003

This study was carried out to evaluate the safety of Korean human milk. The microorganisms were identified from human milk of 149 healthy mothers by two collection methods, hand and pump expression. The means of total bacterial counts were 2.33x10$^4$ cfu/mL on the samples collected by the pump expression and 7.83xl0$^3$ cfu/mL on those collected by the hand expression. Therefore, the total bacterial counts of pump expression samples was 9.80xl0$^2$∼3.06x10$^4$ cfu/mL more than that of hand expression samples. The coliform counts of pump expression was 9.36xl0$^3$∼8.57xl0$^4$ cfu/mL more than that of hand expression. However, there was any significant differences of the lactic acid bacterial counts between the two samples collected by each methods. 100 strains of 5 patterns of total bacterial counts were isolated based on the morphology of colony in the standard plate count agar. 13 species were identified among the isolated strains. The dominant species in Korean human milk were Staphylococcus which 7 subspecies identified(81% in the rate of total bacteria, 1.07x10$^4$ cfu/mL). Other species identified were Micrococcus, Bacillus, Providencia, Pseudomonas, Yersinia and Acinetobacter. 36 strains of 6 patterns of lactic acid bacterial counts were isolated based on morphology of colony in the BCP agar. 7 species were identified among the isolated strains. The dominant species of lactic acid bacteria in Korean human milk were Lactobacillus brevis(50.9% in the rate of lactic acid bacteria, 4.72xl0$^4$ cfu/mL). Others species identified(49.1% lactic acid bacteria) were Lactobacillus curvatus, Lactobacillus delbrueckii subsp. lactis, Lactobacillus acidophilus, Leuconostic lactis and Streptococcus salivarius subsp. thermophilus.

• Korean Journal of Organic Agriculture
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• v.18 no.4
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• pp.527-539
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• 2010

This study was conducted to determine the effect of probiotics as an alternative for antibiotics on growth performance, nutrient digestibility, noxious gas emission and fecal microbial population in growing piglets. A total of 96 piglets ($22.5{\pm}1.3$kg average body weight) were allotted to 3 different treatment groups and replicated 4 times with 8 piglets per replicate in randomized complete block design. Treatments were T1) (Control, basal diet+0.2% antibiotics), T2) 0.2% probiotics complex and T3) 0.3% Bacillus probiotics. During the whole experiment period, there were no differences (p>0.05) in average daily gain (ADG), average daily feed intake (ADFI) and feed efficiency. However, digestibility of dry matter, crude protein, ether extract, nitrogen free extract and crude ash were showed higher in probiotics groups (T2 and T3) than those of control. In noxious gas emission, ammonia, amine, hydrogen sulfide and mercaptan were significantly (p<0.05) reduced in T2 and T3 treatments compared to those in control. Moisture content of feces was not significantly different among treatments. The colony forming units (CFU) of total bacteria, E. coli and thermoduric bacteria in feces were significantly different among treatments. The CFU of total bacteria, E. coli and thermoduric bacteria in T3 treatment were reduced by feeding probiotics B. From this study, we suggest that probiotics A and B are likely able to improve the growth performance and nutrients digestibility, reduce noxious gas emission and change the fecal microbial composition in growing piglets.

• Korean Journal of Poultry Science
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• v.47 no.3
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• pp.169-180
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• 2020

This study examined the effects of a probiotic complex (PC) containing Lactobacillus plantarum, Bacillus subtilis, and Saccharomyces cerevisiae on growth performance, organ weight, immune parameters, fecal microbial count, and noxious odor in broiler chicks. A total of 216 birds (4-day-old) were fed a basal diet (CON) and a diet supplemented with 0.25% (PC1) and 0.5% (PC2) of PC until 35 days of age. No difference in body weight, feed intake, and FCR was observed among the groups. The intestinal mucosal weight of the PC1 group was greater than that of the CON group without affecting weights of the other organs. Intestinal secretory immunoglobulin A (sIgA) levels in the PC2 group increased significantly (P<0.05) compared with that in the CON group. The PC2 group also had a strong tendency for elevated blood sIgA levels. Dietary PC did not affect the level of interleukin-1β in the blood and mucosal tissues or alter maltase, sucrase, and leucine aminopeptidase activities in the intestinal mucosa. The PC2 group had higher colony-forming units (cfu) for L. plantarum and S. cerevisiae, but lower cfu for E. coli than those in the CON group. Compared to the CON diet, the PC2 diet resulted in a decreased H₂S concentration and a tendency toward decreased CH₃SH concentration. In conclusion, a 0.5% PC diet showed increased sIgA and desirable microbial population, and decreased noxious odor in the feces, suggesting that PC could be applied as an environmentally friendly feed additive in broiler chicks.

• The Journal of Korean Academy of Prosthodontics
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• v.62 no.2
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• pp.95-103
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• 2024

Purpose. With the advancement of digital technology, 3D printing is being utilized in the fabrication of denture base. Nevertheless, increasing microbial adhesion to the surface of denture base has been reported as the disadvantage of 3D-printed denture base. The purpose of this study is to investigate the antifungal properties and flexural strength of 3D-printed denture base resin according to the different contents of titanium dioxide nanoparticles. Materials and methods. Titanium dioxide nanoparticles were mixed with the 3D printing resin at the ratios of 0.5, 1, 1.5, and 2 wt%. Twenty specimens per each group were printed in the form of cylindrical shape (diameter: 20 mm, height: 3 mm) to evaluate antifungal properties. Ten specimens from each group underwent polishing using autogrinder, while the remaining ten specimens did not. Candida albicans in hyphae form was inoculated onto each specimen, optical density and colony-forming unit were analyzed. The surface of the specimen was observed using scanning electron microscopy. To evaluate the flexural strength, twenty specimens per each group were 3D printed in the form of rectangular prism shape (length: 64 mm, height: 10 mm, width: 3 mm) and three-point bending tests were conducted using universal testing machine according to ISO 20795-1. Results. Colony-forming unit of C.albicans and optical density of culture medium showed no difference between non-polished groups, but decreased in the polished groups at concentration of 1, 1.5, 2 wt% titanium dioxide nanoparticles. Flexural strength increased with titanium dioxide nanoparticle at concentration of 0.5, 1, 1.5 wt%, but decreased at 2 wt% compared to 1.5 wt%. Conclusion. When 1.5 wt% of titanium dioxide nanoparticles were added to the 3D-printed denture base resin with polishing, antifungal properties were increased.

• Journal of Food Hygiene and Safety
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• v.39 no.2
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• pp.109-117
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• 2024

This study investigated the microbial contamination of agricultural, livestock, and marine ingredients in 55 meal kits distributed across Gyeonggi-do, South Korea. Of the 55 meal kits, 48 contained agricultural ingredients, 43 contained livestock ingredients, and 16 contained marine ingredients. The detection rate of the total aerobic bacteria in the agricultural, livestock, and marine products was 100%. The average numbers of the total aerobic bacteria were 6.57 log colony-forming units (CFU)/g in the agricultural products, 4.60 log CFU/g in the livestock products, and 5.47 log CFU/g in the marine products. The coliform detection rates in the agricultural, livestock, and marine products were 81.25%, 69.77%, and 43.75%, respectively. The average numbers of coliforms were 2.83 log CFU/g in the agricultural products, 1.34 log CFU/g in the livestock products, and 1.12 log CFU/g in the marine products. Escherichia coli was detected in 13 livestock products (30.23%), with levels ranging from 0.70 to 2.36 log CFU/g. Contrastingly, E. coli was detected in only one marine product (6.25%) and was not detected in any agricultural products. The detection rates of fungi in agricultural, livestock, and marine products were 97.92%, 93.02%, and 93.75%, respectively. The average numbers of fungi were 3.82 log CFU/g for the agricultural products, 2.92 log CFU/g for the livestock products, and 2.82 log CFU/g for the marine products. The isolation rates of foodborne pathogens from the agricultural, livestock, and marine products were 35.42%, 37.21%, and 31.25%, respectively. Forty-five foodborne pathogens of seven species, including Bacillus cereus and Salmonella spp., were isolated from the raw materials of the agricultural, livestock, and marine products in 55 meal kits. To prevent foodborne diseases caused by meal kits, it is necessary to focus on washing, heating, and preventing cross-contamination during cooking.

• Journal of dental hygiene science
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• v.14 no.4
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• pp.477-487
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• 2014

Of the many pathogenic Candida species, Candida albicans is the main fungal pathogen of humans. The oral environmental factors considered in the Candida albicans colony forming unit test contain both host and microbial factors associated with candidiasis. In particular, Candida biofilms can develop on surfaces of prosthesis. The purpose of this study was to investigate the distribution of oral Candida species between the type of prosthesis and the situation of oral environment in patient with prosthetic appliance. The patients were 30 elderly subjects with different types of prosthesis, 7 who wore denture, 12 who wore implant and 15 who wore removable orthodontic appliance. We used Candida albicans colony forming unit test using saliva to exam the distribution of Candida albicans related with 5 oral environmental factors, gender, smoking or nonsmoking, alcohol/nonalcohol consumption, the type of prosthetic appliance and its treatment duration as well as tooth brushing frequency per day. In conclusion, for the patient's gender, site in the oral cavity and the type of prosthetic appliance and its treatment duration was associated with an increase in the distribution of Candida albicans in saliva. The distribution of Candida albicans within the oral cavity performs to be modulated to varying extents by oral environmental factors and, further investigations are required to elucidate these complex interactions.

• Journal of dental hygiene science
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• v.13 no.2
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• pp.182-190
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• 2013

Composition of oral microbial flora is suggested to play a role in the maintenance of oral health. Among them, Streptococcus mutans plays an essential role in the formation of dental plaque and it is being noticed as incipient infective bacteria of dental caries. The purpose of this study was to prepare the basic data about distribution of Streptococcus mutans detected from saliva by measuring colony density. It is well known that smoking as well as drinking is a factor of dental caries, however there are few investigations about distribution of Streptococcus mutans either smoking or drinking. The materials of this study were collected from students of dentistry college with general characteristics obtained by self-administered questionnaires. Students were asked to gently chew the paraffin to get saliva for 1 minute. Bacitracin disc in the culture medium was activated for 15 minutes, and then sample was incubated in the activated medium at $37^{\circ}C$ incubator for 48 hours. Streptococcus mutans colonization per 1 ml saliva was measured by the number of criteria. The severe levels of dental caries activity were significantly increased in the case of smoking (from 5.6% to 10%) or drinking (form 0% to 7%), respectively. Also, dental caries activity increased according to smoking and drinking periods longer. However, using the SPSS analytical process (Mann-Whitney's U), no significant differences were observed between the smoking and the non-smoking or the drinking and non-drinking, respectively. These results obtained from dental caries activity of saliva suggest that distribution of Streptococcus mutans following smoking or drinking can be used as a significant information for oral health.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.9
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• pp.1340-1349
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• 2017

Objective: This study aimed to evaluate the microbiological and cellular milk profile for the diagnosis of subclinical mastitis in female buffaloes and to assess risk factors for predisposition of the disease. Methods: Analyses were carried out by standard plate count (SPC), identification of species and antibiotic resistance, somatic cell count (SCC), electrical electrical conductivity of milk (ECM), and lactoferrin content in milk. Teat cups were swabbed to evaluate risk factors, observing hyperkeratosis, milking vacuum pressure and cleanliness of the site. Hence, 30 female buffaloes were randomly selected (15 from a group in early lactation and 15 in late lactation). Results: The most common bacteria in the microbiological examination were Staphylococcus spp., Streptococcus spp. and Corynebacterium sp. In the antibiotic sensitivity test, 10 (58.82%) of the 17 antibiotics tested were sensitive to all isolates, and resistant bacteria were Streptococcus uberis, Streptococcus dysgalactiae, Streptococcus haemolyticus, and Escherichia coli. It was observed that positive samples in the microbiological examination showed total bacterial count between $9.10{\times}10^3$ to $6.94{\times}10^6$ colony forming units/mL, SCC between 42,000 to 4,320,000 cells/mL and ECM ranging from 1.85 to 7.40 mS/cm. It was also found that the teat cups had high microbial counts indicating poor hygiene, and even faults in the cleanliness of the animals' waiting room were observed. It is concluded that values of SCC above 537,000 cells/mL and ECM above 3.0 mS/mL are indications of mammary gland infection for this herd; however, the association of these values with a microbiological analysis is necessary to more accurately evaluate the health status of mammary glands with subclinical mastitis. Conclusion: Through phenotypic characterization of bacteria involved in the samples, the genera Staphylococcus spp., Streptococcus spp., and Corynebacterimum bovis were the most prevalent in this study. Faults in environment and equipment hygienization are factors that are directly associated with mastitis.

• Korean Journal of Food Science and Technology
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• v.49 no.2
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• pp.117-122
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• 2017

The aim of this study was to evaluate the quality characteristics of fresh red paprika treated by electron-beam irradiation at quarantine doses. The initial microbial loads were low with $10^4$ and $10^2$ colony-forming units/g for total aerobic bacteria and coliform, respectively; however, a dose of 1 kGy resulted in load reduction of 1 log cycle. A dose level of more than 1 kGy caused significant decreases in the hardness and carotenoid content parameters. An applied dose level of less than 2 kGy did not affect vitamin C content; however, a decrease of 87-90% was observed after 40-day storage. Samples treated with 2 kGy showed significantly lower acceptance compared to the control, with lower sensory evaluation scores for color and texture. Therefore, e-beam irradiation at dose range of 0.4 and 1 kGy was found to be appropriate for quarantine applications for microbiological control and quality maintenance of paprika.