• Korean Journal of Microbiology
• /
• v.33 no.2
• /
• pp.125-130
• /
• 1997

Microbial reduction of hexava1ent(VI) to trivalent(lII) chromium is regarded as one of the mechanisms that confers resistance to bacteria. In order to verify this hypothesis, we compared Cr(VI) resistance with Cr(VI) reduction among 20 phenotypically distinct environmental isolates from Cr-contaminated and uncontaminated soils. With glucose as an electron donor, Cr(VI) reduction by washed cell suspensions ranged from 0.014 to 0.305 mM Cr(VI) reduced $h^1$. Cr(VI) resistance of the isolates were measured by growth inhibitions on a liquid medium containing 2 mM Cr(VI) based on their decrease of $A_{630}1$ as compared to the controls without Cr(VI). The isolates had a broad range of resistance from no inhibition to 93.4% inhibition of their growth. Upon correlation analysis, there was no significant relationship between those two phenomena. At a population level, a comparison of % resistant viable counts among the Cr-contaminated and uncontaminated soils showed 19.1 % and 0.4% of their total viable counts, respectively. The difference of % resistance between two site,. strongly suggested that the Cr(VI) present in the soils influences natural selection for resistant phenotypes. However, it is unlikely that the Cr(VI) resistance is dependent solely on the reduction as judged by the correlation analysis.

• Food Science of Animal Resources
• /
• v.32 no.4
• /
• pp.441-447
• /
• 2012

In this study, ready-to-cook (RTC) pork bulgogi was investigated microbiologically to determine contamination levels. The investigation was conducted because of an increasing trend in the consumption of RTC meat products in Korea. Ninety marinated RTC pork bulgogi samples were collected from major retail outlets (M), department stores (D), and local markets (L) in Seoul, Korea from March to June 2011. This study examined total plate counts (TPC), Escherichia coli, and coliform bacterial counts, and the presence of Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, Salmonella spp., and E. coli O157:H7. The mean TPC values were 5.89, 6.08, and 5.89 Log CFU/g for M, D, and L, respectively. E. coli was not detected in any sample, but coliforms were present in 72 (80%) of the 90 samples collected. B. cereus, E. coli O157:H7, and Salmonella spp. were not detected; however, S. aureus and L. monocytogenes were detected in five (5.5%) and one (1.1%) of the 90 samples. Samples collected from M and D were contaminated with S. aureus and those from L with L. monocytogenes. These results demonstrate that the conditions under which RTC pork bulgogis are handled and processed are unsanitary.

• Asian-Australasian Journal of Animal Sciences
• /
• v.14 no.5
• /
• pp.631-639
• /
• 2001

Two experiments were carried out concerning the effects of urea-molasses cake (UMC) and its separate components as supplements on rumen environment, in sacco feed degradability and intake of swamp buffaloes fed rice straw, grasses or a mixture of grasses and rice straw. Experiment 1 was a change-over design with 4 animals and 6 treatments. The buffaloes were fed rice straw ad libitum, and the experimental treatments were: no supplementation (R); 700 g of the complete urea-molasses cake (RUMC); 53.2 g urea (RU); 276 g rice bran and 52.5 coconut meal (RRC); 26.6 g salt, 26.6 g bone meal and 2.1 g trace minerals (RMi); and 25 g molasses (RMo). Experiment 2 was a Latin square design with four diets and four animals. The treatments were: rice straw ad libitum and mixed grass (RG) at 2.5 g dry matter per kg live weight (LW); RG plus 700 g urea-molasses cake (RGUMC); mixed grass ad libitum (G); and G plus 700 g cake (GUMC). In both experiments the supplements were fed once daily. In Exp. 1 although the rumen pH was significantly different (p<0.05) among diets, it varied only from 6.90 to 7.06. The ruminal ammonia was also significantly (p<0.05) different among the diets with RUMC significantly higher than R. Total bacterial and protozoal counts were significantly (p<0.05) higher for the RUMC, RU, RMo and RRC diets. Total feed and rice straw intakes were highest for RUMC (p<0.05) and lowest for the RMi and RMo diets, but in sacco degradability of four different roughages were not significantly different among diets. In Exp. 2, rumen pHs of the diets differed significantly and (p<0.01) ranged from 7.04 - 7.19. Ruminal $NH_3-N$ concentrations (mg/100 ml) were also significantly different (p<0.05), and higher for the RGUMC, G and GUMC diets. The total counts of bacteria and protozoa were significantly (p<0.05) higher for the RGUMC, G and GUMC diets. The total feed intake and roughage intake were significantly (p<0.05) higher for the RGUMC, G and GUMC diets compared to the RG diet. Correspondingly, LW changes also differed among treatments (p=0.06). It was concluded that there were significant increases in rumen $NH_3-N$ concentration, microbial populations and feed intake in the buffaloes by UMC supplementation, whereas the significant difference in in sacco DM degradation was not found by any type of supplementation. There seemed to be a need of a combination of urea, molasses, minerals and other protein nitrogen sources to enhance rice straw intake. Adding grass to the rice straw diet at 0.25% LW (DM) should also be considered to maintain buffalo rumen function and production with UMC supplementation, when rice straw is the main roughage.

• Journal of Periodontal and Implant Science
• /
• v.30 no.1
• /
• pp.111-120
• /
• 2000

Purpose We designed this study for the purpose of determining the relationship between periodontal disease activity and PLBW, using the evaluation of probing pocket depth, loss of attachment, gingival index, gingival crevicular fluid amount and subgingival microflora. Methods A total of 100 volunteer mothers(mean age 30.44) at the Department of Obstetrics and Gynecology Seoul National University Hospital were selected for this study.Pregnancy outcomes were categorized into cases and controls in two ways. our definition was based on the following; Group 1 : Any PLBW cases Vs. All NBW controls Group 2 : PLBW cases Vs. NBW controls A periodontal exam was performed on the Ramfjord( #16, 21, 24, 36, 41, 44) teeth and Clinical evaluation consisted of probing pocket depth, loss of attachment, gingival index and gingival crevicular fluid amount. Subgingival plaque samples were collected by three sterile #35 paper points. The total number of anaerobic colonies and aerobic bacteria were enumerated after incubation. Antisera to P. gingivalis, P. intermedia, A. actinomycetemcomitans were produced in white rabbits with live whole cells suspensions. The specific fluorescent bacteria obtained by immunofluorescence and total cell counts obtained by dark-field microscopy were counted on four fields. The percent of each specific microorganism in the total cell count was determined. Results Any PLBW and PLBW cases showed significantly greater probing depth and attachment loss than all NBW and NBW controls. Cases group had significantly increased anaerobic bacterial counts compared with control group and no differences in the other microbes. This study confirmed that periodontal disease is a statistically significant risk factor for PLBW by investigating clinical parameters and subgingival plaque analysis.

• Korean journal of food and cookery science
• /
• v.17 no.6
• /
• pp.617-624
• /
• 2001

Gamma irradiation (1-10 kGy) was applied to chicken for the evaluation of their microbiological safety and possible genotoxicity. In 3 kGy-irradiated sample, the growth of psychrophile was inhibited about 1.5 log cycles and no cells were recovered in total microbial counts. All kinds of contaminated microorganism were sterilized by 7 kGy-irradiation. Also, irradiation followed by freeze-storage at the same time was very effective in inhibiting bacterial growth. The genotoxicity of 10 kGy-irradiated chicken was evaluated by Salmonella Typhimurium reversion assay and in vivo micronucleus assay using mouse bone marrow cells. The results were negative in the bacterial reversion assay with S. Typhimurium TA98, TA100, TA1535, and TA1539. Clastogenic effects were not shown in vivo mouse micronucleus assay at 10 kGy-dose tested.

• Journal of Environmental Health Sciences
• /
• v.37 no.4
• /
• pp.298-305
• /
• 2011

Objectives: There has been a great amount of controversy in the food industry over the effectiveness of using gloves. The objectives of this study were to examine the microbial contamination of food handlers' hands and determine if using gloves could ensure safe handling of foods. Methods: Samples were collected through the glove-juice method from the bare and gloved hands of food handlers at work and were analyzed for the presence of aerobic plate counts, total coliform, fecal coliform, Escherichiacoli, Staphylococcus aureus, and Salmonella spp. Microbiological testing was conducted according to the Food Code of Korea. Results: Microbial contamination was consistently higher with bare hands than with gloved hands, although the microbial loads on both hands increased over time. Under certain conditions, there were significant differences between the bacterial loads on bare and on gloved hands (p<0.05). E. coli, S. aureus, and Salmonella spp. were still alive on both bare and gloved hands at the time the food handlers finished their work. Conclusions: Wearing gloves was associated with a marked reduction of bacterial contamination of the hands. However, the practice of continuously wearing gloves during food handling increases the potential for cross-contamination of bacteria. The findings of this study emphasize the need for a rational use of gloves, and strict adherence to hand hygiene compliance among food handlers.

• Food Science of Animal Resources
• /
• v.34 no.6
• /
• pp.792-798
• /
• 2014

The distribution channel of meat by-products from the pig farm to the final consumer can include a meat processor, wholesale market, wholesaler, retailer, and butcher shop. Bacterial contamination at any of these steps remains to be a serious public health concern. The aim of this study was to evaluate the distribution channel and microbial characteristics of pig by-products in Korea. Upon evaluation of pig by-products in cold storage, we found that the small and large intestine were significantly (p<0.05) higher in pH value compared to the heart and liver. The total plate counts were not significantly different among offals until cold storage for 7 d. The coliform count after 1 d of cold storage was significantly (p<0.05) higher in small and large intestine than in the other organs. The coliform count of heart, liver, and stomach showed a higher coliform count than small and large intestine until 7 d of cold storage. As determined by 16S rRNA sequencing, contamination of major pig by-products with Escherichia coli, Shigella spp., and other bacterial species occurred. Therefore, our results suggest that a more careful washing process is needed to maintain quality and hygiene and to ensure the safety of pig by-products, especially for small and large intestine.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.28 no.4
• /
• pp.766-772
• /
• 1999

In order to improve funtionality of kochujang, red ginseng powder(1, 2 and 5% red ginseng on the total weight basis) was added to the raw material of kochujang. Changes in moisture content, microflora and enzyme activities were investigated in control kochujang(Sunchang kochujang) and red ginseng added kochujang during fermentation at 25oC for 120 days. Kochujang samples fremented for 90 and 120 days were subjected to sensory evaluation test. As the fermentation progressed, the moisture content and titratable acidity were gradually increased whereas pH was decreased. However, red ginseng had no effects on those changes. Bacterial count was maintained at the level of 107 CFU/g during fermentation. The level of yeast count was 104 CFU/g at the early stage of fermentation and increaed to 107 CFU/g after 60 days of fermentation and then maintained at 107 CFU/g. Red-ginseng had no effects on bacterial and yeast counts of kochujang. Amylase activity was gradually reduced during fermentation. Amylase activity was increased until 60 days of fermentation and then reduced by 90 days of fermentation. Acidic protease activity was slightly reduced at the initial stage of fermentation and then rapid increased. Acidic protease activity was at the highest level after 120 days of fermentation. Red ginseng did not alter those enzyme activities of kochujang. There were no differences in sensory properties between kochujang samples fermented for 90 and 120 days of fermentation. The addition of red-ginseng did not affect such sensory properties of kochujang as color, odor, hot taste and salty taste, but overall preference appeared to be improved by red ginseng addition.

• Preventive Nutrition and Food Science
• /
• v.1 no.1
• /
• pp.23-29
• /
• 1996

This study was conducted to investigate the changes in chemical, microbial and sensory characteristics, and antimutagenicity of buchu(leek, Allium odorum) kimchi during fermentation at 15$^{\circ}C$. Reducing sugar contents and pH of buchu kimchi were decreased during the fermentation. The reduction rate of reducing sugar of glutinous rice paste and shrimp added buvhu kimchi(GSBK) was faster than those of control buchu kimchi(CBK) and glutious rice paste added bucku kimchi(GBK). Acidity increased rapidly until 4 days,a nd optimum acidity (0.6%) of bucku kimchi was reached within 2 day. Also total bacterial and lactic acid bacterial counts greatly increased after 4 days of the fermentation. The numbers of lactic acid bacteria after 8 day- fermentation in CBK and GSBK, and 10 day-fermentation in GBK were the highest values, 4.5$\times${TEX}$10^{8}${/TEX} CFU/ml, 4.8$\times${TEX}$10^{8}${/TEX} CFU/ml and 6.1$\times${TEX}$10^{8}${/TEX} CFU/ml, respectively. In the sensory evaluation, appearance of sample was good at 0 day, taste from overall quality of buchu kimchi were asquired the highest values at 6th day. The methanol extracts from buchu kimchi(GBK) showed antimutagenicity against aflatoxin {TEX}$B_{1}${/TEX}({TEX}$AFB_{1}${/TEX})in Salmonella typhimurium TA100. The inhibition ration were 58~69% with treatment of the 5% methanol extracts, and when the adding concentration increased the effect increased.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.16 no.4
• /
• pp.268-277
• /
• 1987

The changes of the aerobic viable bacterial counts, the content of chemical components and the sensory evaluation in Kimchis which were prepared with Various ingredients (red pepper, green onion, garlic and ginger) and fermentation at $20^{\circ}C$ were investigated. Aerobic viable bacterial counts were suddenly decreased with fermentation, but it was decreased slowly from the second day. Salinity of Kimchis was $1.8%{\sim}2.0%$ and titratable acidify were lower in sample 2 (deleted red pepper) and 3 (deleted green onion) on the first day but sample 4 (deleted garlic) after the fifth day. Total sugar content was decreased from $1.8{\sim}2.7g/100g$ to $0.8{\sim}1.1g/100g$ during fermentation periods. Carbon dioxide content maintained relatively higher in sample 2 and 5 (deleted ginger) with fermentation. Volatile organic acid content showed no difference in all Kimchis with fermentation. During the whole fermentation period, appearance was the worst in sample 2. Texture, off-flavor and overall-eating quality were the worst in sample 4. Carbonated flavor and overall eating quality were the best in sample 5.