• Korean Journal of Microbiology
• /
• v.49 no.4
• /
• pp.360-368
• /
• 2013

Recently interactive water fountains are gaining popularity in making public facilities in South Korea. The total number of interactive fountains is rapidly growing at the rate of >50% annually. In this study, we performed quantitative microbial risk assessment to estimate infection risks in children by Legionella spp. while playing in interactive fountains. The exposure dose for a given concentration of Legionella in water was calculated using water-aerosol partition rate of Legionella, exposure duration, inhalation rate, and deposit rate of aerosols in the lungs following inhalation. The dose was converted to infection risk by using the dose-response function developed for L. pneumophila. High weight and/or old children, i.e., 12-year children, running around in fountains were the highest risk group by showing >0.05 infection probability for fountain waters containing ${\geq}10^4$ CFU/L Legionella. The result supported the current guideline by Korea Centers for Disease Control and Prevention, which permits use of water with < $10^3$ CFU/L Legionella cells for all purposes. However, the results still warrant further evaluation of the guideline to accommodate risks for children because the dose-response relationship in the model was developed for healthy adults. Further risk assessment studies need to be conducted by employing dose-response model for children who generally carries weaker immune system than adults.

• Korean Journal of Microbiology
• /
• v.47 no.1
• /
• pp.66-73
• /
• 2011

Bacterial density distributions of gut microbes in the digestive organs of Harmonia axyridis collected from three different sources (JK, CK, and CJ) were $6.0{\times}10^4$ CFU/gut under aerobic culture condition and $8.0{\times}10^6$ CFU/gut under anaerobic culture condition. Seven colony types were observed under aerobic condition and three types of similarity were detected under anaerobic condition. In total, 116 strains, including 34 strains under aerobic condition, were isolated from the digestive organs of H. axyridis. Based on the analysis of the 16S rRNA gene sequence, aerobic gut microbes were assigned to the Proteobacteria, Actinobacteria, Firmicutes, and Deinococcus-Thermus. A large number of isolates belonged to the genus Bacillus and Staphylococcus of the Firmicutes commonly found in H. axyridis from different sites. Anaerobic gut microbes were found to be similar according to colony morphological, phylogenetic analysis using ARDRA. Eighty-two anaerobic gut microbes were clustered into 17 different ARDRA types according to HaeIII. Representative anaerobic gut microbes in each ARDRA group were divided into five species of ${\gamma}$-Proteobacteria based on 16S rRNA gene sequence analysis; Hafnia alvei, Enterobacter ludwigii, Enterobacter kobei, Pseudomonas oryzihabitans and Pseudomonas koreensis. Phylogenetic analysis indicated that about 70% of the isolates belonged to ${\gamma}$-Proteobacteria, suggesting predominance of gut microbes.

• Journal of Environmental Science International
• /
• v.23 no.8
• /
• pp.1429-1436
• /
• 2014

In this study, we investigated the effects of dietary supplementation (n = 40 pigs/treatment) with bamboo powder (0, 1, 2 and 3%) for 38 days. We evaluated growth performance, blood metabolites, and carcass characteristics of fattening pigs and gas emission and microbial populations in pig manure, to obtain data on pork producers for environmental management. We obtained the following results. First, supplementation with increasing amounts of bamboo powder had a significant (P < 0.05) effect on feed intake, feed efficiency, and glucose contents (except for initial and final body weight, weight gain, carcass characteristics, and blood urea nitrogen). In terms of blood metabolites, glucose and blood urea nitrogen tended to decrease with increasing amounts of bamboo powder. Second, the amounts of ammonia, methane, amine, hydrogen sulfide, and acetic acid were reduced by increasing amounts of bamboo powder when compared with the controls (P < 0.05). However, there were no significant differences in pH, propionic acid, iso-butyric acid, butyric acid, iso-valeric acid, and valeric acid among all treatments. The lowest gas emission was observed when 3% bamboo powder was used. Third, supplementation with increasing amounts of bamboo powder tended (P < 0.05) to increase the total number of bacteria, Lactobacillus spp., and yeast, but E. coli, Salmonella spp., and Shigella spp. were not detected in any treatment. In conclusion, the results of this study suggest that supplementation with bamboo powder was effective in reducing gas emission and inhibiting pathogen populations in pig manure by lowering the pH of the manure.

• Korean journal of food and cookery science
• /
• v.21 no.4 s.88
• /
• pp.545-555
• /
• 2005

The physicochemical and microbial characteristics of Oiji prepared with dry salting method, which has been used industrially for industry, were investigated. Low salting and low storage temperature were employed:extremely low salting extremely low temperature; ESET $(5\%,\;0^{\circ}C)$, very low salting extremely low temperature;VSET $(10\%,\;0^{\circ}C)$, extremely low salting very low temperature; ESVT$(5\%,\;5^{\circ}C)$, low salting very low temperature; VSVT$(10\%,\;5^{\circ}C)$ and high salting low temperature;HSLT$(30\%,\;10^{\circ}C)$ for control. Acidity was lower, and pH was higher in VSET, in of which the fermentation pattern was similar with that of HSLT The time required to reach the optimum acidity ($0.3\%$ lactic acid) was longer delayed for VSET (168 days), than for compared to ESVT (51 days). During storage of Oiji, greenness (-a) as measured with of the Hunter color system wasshowed the highest in VSET, and the lowest while in ESVT, the lowest. Total microbial and lactic acid bacteria counts number were the lowest in HSLT and VSET and were the lowest than in other groups, while the highest in ESVT. Yeast was not detected in HSLT, but was the highest while in VSVT. E coli coliform and listeria were detected in the $5\%$ salting groups, although Salmonella was not detected in any of the all groups. Texture profile analysis demonstrated exhibited that fracturability and hardness were highest in HSLT and VSET, compared to the other groups. Scores of over-all preference for ESVT and HSLT were higher atwith 6.3 and 6.2, respectively, compared to the other products. Based on these results, lower saltiness less than $10\%$ and lower storage temperature (less than $5^{\circ}C$) condition was optimum for maximizing the better for good quality of industrial Oiji preparation in industry.

• Food Science of Animal Resources
• /
• v.28 no.5
• /
• pp.574-579
• /
• 2008

To develop a yogurt for sensitive consumer such as infants, children or immuno-compromised patients using gamma irradiation, the effects of gamma irradiation on the microbiological, chemical, and sensory quality in a commercial plain yogurt were investigated. No viable coliform bacteria were detected in the sample and approximately a 6 decimal reduction was achieved in the number of total aerobic bacteria by irradiation at 5 kGy. The initial population of lactic acid bacteria observed in the commercial plain yogurt was 8.95 log CFU/g. Gamma irradiation significantly reduced the initial microbial level to 6.47 and 2.85 log CFU/g after irradiation at 1 and 3 kGy, respectively (p<0.05). However, irradiation dose up to 5 kGy could not completely eliminate the lactic acid bacteria in commercial plain yogurt. pH, color, lactose and lactic acid content, and sensory quality were not affected by irradiation treatment and storage. Our results suggest that irradiation can improve the microbial quality of commercial plain yogurt without impairing the physicochemical and sensory quality.

• Food Science of Animal Resources
• /
• v.22 no.3
• /
• pp.228-233
• /
• 2002

To investigate the effects of submersion aging in chilled water on tenderness and microbial growth of vacuum-packed beef, the semimembranosus muscles of Hanwoo (Korean cattle) was sampled at a commercial meat plant at 24 hrs postmortem. The samples were cut to 2.5 cm thick steaks and randomly assigned to following two treatments. The samples were stored in conventional refrigerator at 4$^{\circ}C$ after vacuum packaging for control whereas the other vacuum-packed samples were submersed in chilled water at 1$^{\circ}C$ for treatment, and both samples were stored for 14 days to measure total plate counts (TPC), sarcomere length, free calcium concentration, shear farce value and myofibrillar fragmentation index (MFI). The sarcomere length of treatment was significantly (p<0.05) longer than that of control at 3 days aging. Result suggested that submersion in chilled water of vacuum-packed beef might be effective to improve tenderness of meat compared to storage in conventional refrigerator. There were no significant differences in the shear force and MFI between control and treatment during storage. However, the free calcium concentration of samples from treatment was significantly (p<0.05) higher than that of control at 7 days of ageing. This result indicated that the lower shear force value and the longer sarcomere length of samples from treatment might be due to increasing the free calcium ion concentration in sarcoplasm during storage. On the other hands, samples from control showed significantly (p<0.05) higher number of microbial (TPC) compared to treatment during storage. from results obtained, submersion in chilled water of vacuum-packed beef could be recommended as a desirable aging method to improve tenderness of Hanwoo compared to aging in conventional refrigerator.

• Korean Journal of Poultry Science
• /
• v.34 no.1
• /
• pp.23-29
• /
• 2007

Rare earth(RE) is a common name indicating 17 of specific elements including 15 of lanthanides, scandium (Sc), and yttrium(Y). This study was conducted to compare the effect of RE to growth stimulating antibiotic products in broiler diet. One of the products commonly used in broiler feeding, Chlorotetracycline(CTC) was used at a level of 200ppm for the antibiotic treatment and replaced by 100ppm RE for the RE treatment. Dietary addition of RE and CTC showed similar effects in improving broiler growth and feed conversion each other, and those were significantly better when compared to those of the control group(P<0.05). Abdominal fats of chicks fed RE were significantly lower than others(P<0.05). Intestinal E. coli and total microbial numbers were reduced by RE addition(P<0.05), but the number of Lactobacillus was not affected. The number of Salmonella was also decreased but it was not significant.

• Journal of Food Hygiene and Safety
• /
• v.18 no.1
• /
• pp.14-24
• /
• 2003

Two aims of the present study were the evaluation of hygienic, microbial safety on food services of elementary schools in Western Gyeongnam province, and then, the construction of database for the SSOP (Sanitation Standard Operation Procedures) practice. A total of 98 samples were collected from drinking water, waterworks, kitchen utensils, kitchen equipments, employees and cooked foods. Total bacteria was counted and pathogenic bacteria such E. coli, salmonella, yersinia, vibrio parahaemolyticus and staphylococcus were identified based on the biochemical analysis. Following are the results: the number of bacteria showed from 1.0x10$^2$CFU/ mL to 1.0x10$^{6}$ CFU/mL in most samples, which the level exceeds normal range. Over 1.0x10$^{5}$ CFU/ml bacteria were observed from the kimchi in 4 places (B, C, D, E), because cooked food such as kimchi had not been heated. As a rule, the bacterium level in place B was higher than that in any of the other places. E-coli were isolated from kitchen knives (C, E) and Kimchi (E): staphylococci were isolated from drinking water (A), hands (D), refrigerator (E) and apron (E). But, salmonella, vibrio and yersinia were not detected in anywhere. In conclusion, the presence of bacteria and pathogenic agents in school food service was closely related to hygienic practice. For that reason, it is necessary to have more systematic and efficient management in order to enhance the food safety.

• Korean Journal of Poultry Science
• /
• v.33 no.1
• /
• pp.81-95
• /
• 2006

The large intestine of the chicken differs both anatomically and physiologically from the pig's large intestine and the men of the cow. The chicken's large intestine is less developed than the pig's large intestine or the cow's lumen. This paper summaries these differences. The chicken's large intestine contains a microbiological population similar to that found in the rumen. The chicken's caeca especially contains a large number of microorganisms, but this population varies according to age, fred, maturity, antibiotic use and etc.. Protein is an essential nutrient for the formation of intestinal microvilli. A study showed that the length of the small intestine was 63 % of the total gastrointestinal tract (GIT) length, while caecum was 8.1 %, and the colon and rectum were 4.6 %. The establishment of the microbial population of the small intestine occurs earlier than that of the caeca, but the identity of approximately 90 % of microbial population of the chicken GIT is hon. Recent studies have shown that energy, volatile fatty acid (VFA) and electrolytes that are found in the large intestine may be absorbed to a certain degree. The chicken small intestine is the primary location for digestion with a variety of enzymes being secreted here. Much research is being conducted into the digestion of sucrose thermal oligosaccharide caramel (STOP), fructooligosaccharides (FOS), mannanoligosaccharide (MOS), galactooligosaccharides (GOS) and isomalto-oligosaccharides (IMO) in the chicken caeca and large intestine. Excessive fibre content in the feed has detrimental effects, but proper fibre supplementation to chicken diets can improve the length and capacity of the small intestine.

• Korean Journal of Poultry Science
• /
• v.34 no.4
• /
• pp.287-294
• /
• 2007

Current study was conducted to identify the effects of dietary supplementation of Aspergillus oryzae ferments (AOF) cultured under normal (NAOF) or nitrogen-deficient (NMAOF) environment on feed efficiency, nutrient digestibility for broiler chicks. Fecal microbes and ammonia gas production were also determined. A total of 168 male Avian chicks, 2-wk-old, were randomly assigned into 56 cages, three chicks per cage. There were seven treatments (Control, NAOF 0.05, 0.1, 0.5%, NMAOF 0.05, 0.1, 0.5%), with 8 replicates (cages) per treatment. There was no significant difference in nutrient digestibility between two AOF groups, but the digestibility was greatly(p<0.05) improved by AOF supplementation. Total microbial account significantly (p<0.05) differed between the treatment groups with the highest number for NNAOF, followed by NAOF and control. In the case of Escherichia coli and Salmonella, the AOF supplementation significantly (p<0.05) reduced their numbers in feces, with a particular reduction in NNAOF group. Levels of ammonia gas generation were in order of control>NAOP>NNAOP. The current data implied that AOF supplementation, particularly grown under nitrogen-deficient environment, would be a feasible way to improve feed efficiency for broiler production, as well as to reduce environmental cost. However, further studies remain for industrial application.