• Title/Summary/Keyword: yeast and molds

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Comparison of Irradiation Effect of Different Radiation Types on Decontamination of Microorganisms in Red Pepper Powder (고춧가루 오염 미생물의 제어에서 방사선종별 조사 효과)

  • Park, Kyung-Sook
    • Journal of Radiation Industry
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    • v.8 no.1
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    • pp.1-5
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    • 2014
  • This study investigated the reduction of microbial population and sensory properties in red pepper powders irradiated by gamma ray, electron beam, and X-ray. Populations of total aerobic bacteria and yeast & molds in red pepper powders were decreased by irradiation treatment in a dose-dependent manner. Gamma ray, electron beam, and X-ray at doses above 8 kGy caused 100% inhibition on growth of aerobic bacteria in red pepper powders. Inhibitory activity of X-ray on sterilization of red pepper powders was significantly equal to or higher compared to gamma ray and electron beam. Color and off flavor in red pepper powders were no significant difference among the control and samples irradiated with gamma ray, electron beam, and X-ray. As a result, the gamma ray, electron beam, and X-ray irradiation can be used to sterilize the microbial growth in red pepper powders without quality loss.

Studies on the Pasteurization Conditions of Takju (탁주의 저온 살균조건에 관한 연구)

  • Lee, Cherl-Ho;Tae, Won-Taek;Kim, Gie-Myung;Lee, Hyun-Duck
    • Korean Journal of Food Science and Technology
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    • v.23 no.1
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    • pp.44-51
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    • 1991
  • The thermal resistance of the important microorganisms in takju. Korean traditional turbid alcoholic beverage, was measured and optimun heating time and temperature to achieve the commercial pasteurization of these microorganisms were examined. Most of the vegetative bacterial cells in takju were destroyed by heating at over $60^{\circ}C$, except for the spore forming organisms, which did not actively grow in takju after pasteurization. The important microorganisms for the quality deterioration of pasteurized takju were then appeared to be yeast and molds, and their thermal resistances were measured. The thermal resistances of these microorganisms changed greatly depending upon the heating method. The D values of yeast in takju were 3.5 min at $65^{\circ}C$ and 0.46 min at $80^{\circ}C$ in cap-tube, and 7.1 sec at $65^{\circ}C$ and 2.3 sec at $80^{\circ}C$ in a continuous coil heat exchanger. Those of molds were 2.7 min at 65℃ and 0.25 min at $80^{\circ}C$ in cap-tube, and 3 sec at $65^{\circ}C$ and <1 sec at $80^{\circ}C$ in the coil heat exchanger. The acidity and pH did not change at $30^{\circ}C$ for two weeks after pasteurization by heating in the coil heat exchanger at $65^{\circ}C$ for 17 sec, but the viscosity increased slightly by the heat treatment. Significant differences in sensory quality, especially the formation of burnt smell and bitterness by heating takju for 12D of yeast at $70,\;80\;and\;85^{\circ}C$, respectively, were observed and this resulted in the significant reduction in overall likeness of pasteurized takju. However, when the heating temperature was fixed to $80^{\circ}C$, the overall likeness of pasteurized takju did not affected significantly by the heating time ranging from 8D to 12D of yeast. It was concluded that the optimum pasteurization condition of takju in a continuous heat exchanger was heating at $80^{circ}C$ for 23sec(10D of yeast).

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Combined Treatment of Aqueous Chlorine Dioxide, Organic Acid, and Blanching for Microbial Decontamination of Wild Vegetables after Harvest (수확 후 산채류의 미생물 제어를 위한 이산화염소수와 유기산 및 Blanching 병합 처리)

  • Kang, Ji Hoon;Park, Shin Min;Kim, Hyun Gyu;Son, Hyun Jung;Lee, Ka Yeon;Kang, Kil-Nam;Park, Jong Tae;Song, Kyung Bin
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.45 no.2
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    • pp.277-283
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    • 2016
  • To improve the microbiological safety of wild vegetables after harvest, Aster scaber and Cirsium setidens Nakai were treated with combinations of 50 ppm aqueous chlorine dioxide ($ClO_2$)/0.5% citric acid or fumaric acid, and 50 ppm $ClO_2$/0.5% fumaric acid/blanching at $90^{\circ}C$ for 2 min. Combined treatment of 50 ppm $ClO_2$ and 0.5% citric acid reduced populations of total aerobic bacteria, yeast, and molds in Aster scaber and Cirsium setidens Nakai by 2.80~3.64 and 2.02~2.67 log CFU/g, respectively, compared to those of the control. Combined treatment of 50 ppm $ClO_2$ and 0.5% fumaric acid reduced total aerobic bacteria, yeast and molds populations by 3.62~3.82 and 2.47~3.02 log CFU/g, respectively. Based on the results, combined treatment of $ClO_2$ and fumaric acid was more effective in controlling microorganisms in the wild vegetables than either $ClO_2$ or citric acid. In addition, combined treatment of $ClO_2$/fumaric acid/blanching reduced the populations of total aerobic bacteria by 4.59~5.12 log CFU/g, and populations of yeast and molds were not detected by treatment. These results suggest that combined treatment of $ClO_2$/fumaric acid/blanching is the most effective method for improving microbiological safety of wild vegetables after harvest.

Effects of Aqueous Chlorine Dioxide and UV-C Irradiation on Decontamination and Growth of Microbes during Chilled Storage of Celery and Cherries (이산화염소수, Ultraviolet-C 또는 병합처리가 샐러리와 체리에서의 살균 및 냉장저장 중 미생물 성장에 미치는 효과)

  • Song, Hyeon-Jeong;Chun, Ho-Hyun;Jo, Wan-Sin;Song, Kyung-Bin
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.41 no.3
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    • pp.402-407
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    • 2012
  • The effects of a combined treatment of aqueous chlorine dioxide ($ClO_2$) and ultraviolet-C (UV-C) irradiation on microbial growth in celery and cherries were investigated. Celery and cherry samples were treated with 50 ppm $ClO_2$, UV-C at dose of 10 kJ/$m^2$, and a combination of $ClO_2$ and UV-C. The changes in the counts of Escherichia coli O157:H7 inoculated in the celery and cherries as well as those of total aerobic bacteria, yeast and molds in the celery and cherries were investigated after each treatment. After the combined treatment of aqueous $ClO_2$ and UV-C irradiation, the populations of E. coli O157:H7 in the inoculated celery and cherries were reduced by 2.8 and 3.0 log CFU/g, respectively, compared to those of the control. For the un-inoculated celery and cherries, the populations of total aerobic bacteria were reduced by 2.9 and 1.8 log CFU/g, respectively, compared to the control. In addition, the populations of yeast and molds were decreased by 1.8 and 1.2 log CFU/g, respectively. These results suggest that the combined treatment of 50 ppm $ClO_2$ and UV-C at a dose of 10 kJ/$m^2$ would be an effective technology for decontamination and improving the microbiological safety in celery and cherries during chilled storage.

Pulmonary Fungal Infection in Patients with Tuberculosis or Other Lung Diseases and Fungal Flora in Human Sputum Specimens (폐결핵 또는 기타 폐질환 환자에서의 진균감염과 객담으로부터 분리되는 임상적유의 및 무의진균에 관한 연구)

  • Kim, Sang-Jae;Hong, Young-Pyo;Kim, Sin-Ok;Lee, Ho-Won;Lee, Seok-Gi
    • The Journal of the Korean Society for Microbiology
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    • v.22 no.1
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    • pp.15-22
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    • 1987
  • Pulmonary fungal infection has been investigated in patients with healed or active pulmonary tuberculosis or other lung diseases by demonstrating serum precipitating antibodies to the various fungal antigens and by isolating the related fungi from sputums or other clinical specimens. Out of 1,192 suspected patients, 405(34.0%) showed precipitin bands on immunodiffusion tests and the related fungi have been demonstrated in sputums or other specimens of 79.5% of them(327) whose specimens had been cultured. Three patients did not have precipitating antibodies to any fungal antigen, but the same fungus was repeatedly isolated from sputums of two patients for over one year of period and from open lung biopsy specimen in the other patient. Most commonly involved species in pulmonary infection were A. fumigatus(70.3%) and C. albicans (at least 23.8%), followed by A. flavus, P. boydii, A. nidulans, etc. Out of fungi isolated from individuals(459), who were apparently not infected with fungi, molds were 66.0% and the rest, yeasts. Most commonly encountered molds were aspergilli(31.7%), followed by penicilli(16.3%), Cladosporium spp.(2.8%), Fusarium spp.(2.2%), etc. C. albicans(16.6%) was of course most common yeast in human sputums and the other species were seen in few.

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Changes of Indicator Microorganisms and Pathogenic Bacteria in Spinach during Cook-Chill Process (시금치의 cook-chill 가공 중 오염지표균 및 병원성세균의 변화)

  • Kim, Hye-Jung;Park, Jae-Kap;Lee, Dong-Sun;Paik, Hyun-Dong
    • Korean Journal of Food Science and Technology
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    • v.34 no.5
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    • pp.927-930
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    • 2002
  • Spinach minimally processed using cook-chill and sous vide techniques was vacuum-packed in low gas permeable plastic film, pasteurized at $70^{\circ}C$ for 2 min, cooled rapidly at $3^{\circ}C$, and stored at 3 and $10^{\circ}C$. Contents of mesophilic bacteria, psychrophilic bacteria, anaerobic bacteria, spore-forming bacteria, total coliforms, yeast and molds, fecal Streptococcus, and Enterobacteriacea were measared to identify the degree of food contamination. Number of mesophilic bacteria, detected at $2.2{\times}10^8\;cfu/g$ in raw spinish, decreased to about $6.0{\times}10^3\;cfu/g$ after cook-chill process. During the storage at 3 or $10^{\circ}C$, levels of mesophilic, psychrophilic and anaerobic bacteria increased, whereas total coliforms, yeast and molds, fecal Streptococcus, and Enterobacteriacea were not detected. Twelve strains of Aeromonas hydphila, Escherichia coli O157:H7, Plesiomonas shigelloides, Pseudomonas aeruginosa, Salmonella spp., Shigella spp., Yersinia enterocolitica, Bacillus cereus, Campylococcus spp., Clostridium perfringens, Listeria monocytogenes, and Staphylococcus aureus were examined for detecting the presence of pathogenic bacteria in spinach. B. cereus and C. perfringens were isolated from raw, washed, and cook-chilled spinach, whereas A. hydrophila was isolated only from washed spinach. S. aureus was isolated from raw and washed spinach, but not from cook-chilled spinach. Other pathogenic organisms were not detected in raw, washed, and cook-chilled spinach.

Contamination level of commercialized pepper and sterilization effect by intense pulsed light in batch system (시중 판매 후추의 오염도 및 회분식 광펄스 처리에 의한 살균 효과)

  • Park, Jihyun;Shin, Jung-Kue
    • Korean Journal of Food Science and Technology
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    • v.48 no.5
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    • pp.525-529
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    • 2016
  • Twenty-nine pepper products commercially available in the market were collected and investigate for contamination levels. Pepper products purchased from traditional markets had a degree of contamination of $10^6-10^7CFU/g$ aerobic bacteria, $10^4-10^5CFU/g$ Bacillus sp., and less than $10^2CFU/g$ yeast and molds. Organic pepper showed a degree of contamination of $10^4$ aerobic bacteria, $10^2-10^3$ Bacillus sp., and less than $10^1$ yeast and molds. Intense pulsed light (IPL) treatment of 10 min (1,000 V, 5 pps and 4 cm sample-to-lamp distance) showed a bacterial death rate of 1.45-1.55 log for whole peppers, and of 0.8-0.85 log for black and white pepper powder. The sterilization rate using IPL was higher than that using other non-thermal sterilization methods, such as ozone treatment or low-pressure discharge plasma sterilization, indicating that the IPL sterilization method may find potential application in the industry. However, further studies may need to be conducted to enhance the effect of sterilization.

Improvement of Hygienic Quality of Panax Ginseng Leaf Tea (고려인삼 엽록차의 위생적 품질개선 연구)

  • 이영주;김종군;권중호;변명우;김석원;조한옥
    • Journal of Food Hygiene and Safety
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    • v.5 no.1
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    • pp.13-19
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    • 1990
  • The microbial populations of exportable ginseng leaf tea were $3.6{\times}10^{5}/g$ in mesophilic aerobic bacteria, $2.1{\times}10^{3}/g$ in mesophilic aerobic spores, $1.6{\times}10^{4}/g$ in yeast, $1.9{\times}10^{4}/g$ in molds and $1.2{\times}10^{4}/g$ in coliforms, respectively, which are higher levels than the legaJIy permissible loads of microorganisms for ginseng powders in Korea. In a comparative study of the decontaminating effects on microorganisms, ethylene oxide fumigation and 5 kGy irradiation could decrease microorganisms below the detectable level. And there is no growth of microorgllnisms after three months of storage at $30{\pm}1^{circ}C$. The decimal reduction doses (Dw value) for microorganisms contaminated were 0.70 kGy in coliforms, 0.75 kGy in total bacteria, 0.85 kGy in molds. and 0.95 kGy in yeast, respectively. In the organoleptic test for ginseng leaf tea, the irradiated samples showed no significant difference from the control group in overall flavor, taste, color and acceptability. However the extracts of ethylene oxide fumigated sample were significantly different in color and taste from other groups even after three months storage.

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Radicidation of the Condiment for Soup of Instant Noodle(Ramen) (즉석라면 스-프의 감마선 살균)

  • Byun, Myung-Woo;Kwon, Joong-Ho;Cha, Bo-Sook;Cho, Han-Ok;Kang, Se-Sik
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.18 no.1
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    • pp.14-18
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    • 1989
  • Comparative effects of gamma irradiation and ethylene oxide treatments on the sterilization and physicochemical propperties of the condiment for soup of instant noodle (ramen) were investigated. The number of microorganisms contaminated ranged from $10^3\;to\;10^7\;CFU/g$ in total bacterial count, which were mainly composed of thermophiles and acid tolerant bacteria by over 90%. The yeast & molds were contaminated by $10^2\;to\;10^3\;CFU/g$. In the sterilizing effect of an irradiation on the microorganisms contaminated, 7 to 10 kGy gamma irradiation could eliminated yeast & molds, and also bring about the reduction of total bacterial count to below $10^3\;CFU/g.\;D_{10}$values of total bacteria! count of the samples ranged from 2.33 to 3.33 kGy. In comparative effects of irradiation and ethylene oxide treatments on the physicochemical properties of the sample, both treatments affected more or less rancidity, color, and amino-Ncontent, but less than 10 kGy irradiation was shown to be safe than ethylene oxide.

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Effects of Dietary Synbiotics from Anaerobic Microflora on Growth Performance, Noxious Gas Emission and Fecal Pathogenic Bacteria Population in Weaning Pigs

  • Lee, Shin Ja;Shin, Nyeon Hak;Ok, Ji Un;Jung, Ho Sik;Chu, Gyo Moon;Kim, Jong Duk;Kim, In Ho;Lee, Sung Sill
    • Asian-Australasian Journal of Animal Sciences
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    • v.22 no.8
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    • pp.1202-1208
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    • 2009
  • Synbiotics is the term used for a mixture of probiotics (live microbial feed additives that beneficially affects the host animal) and prebiotics (non-digestible food ingredients that beneficially affect the organism). This study investigated the effect of probiotics from anaerobic microflora with prebiotics on growth performance, nutrient digestibility, noxious gas emission and fecal microbial population in weaning pigs. 150 pigs with an initial BW of 6.80${\pm}$0.32 kg (20 d of age) were randomly assigned to 5 dietary treatments as follows: i) US, basal diet+0.15% antibiotics (0.05% oxytetracycline 200 and 0.10% tiamulin 38 g), ii) BS, basal diet+0.2% synbiotics (probiotics from bacteria), iii) YS, basal diet+0.2% synbiotics (probiotics from yeast), iv) MS, basal diet+0.2% synbiotics (probiotics from mold), v) CS, basal diet+0.2% synbiotics (from compounds of bacteria, yeast and mold). The probiotics were contained in $10^{9}$ cfu/ml, $10^{5}$ cfu/ml and $10^{3}$ tfu/ml of bacteria, yeast and molds, respectively. The same prebiotics (mannan oligosaccharide, lactose, sodium acetate and ammonium citrate) was used for all the synbiotics. Pigs were housed individually for a 16-day experimental period. Growth performance showed no significant difference between antibiotic treatments and synbiotics-added treatments. The BS treatment showed higher (p<0.05) dry matter (DM) and nitrogen digestibility while ether extract and crude fiber digestibility were not affected by the dietary treatment. Also, the BS treatment decreased (p<0.05) fecal ammonia and amine gas emissions. Hydrogen sulfide concentration was also decreased (p<0.05) in BS, YS and MS treatments compared to other treatments. Moreover, all the synbioticsadded treatments increased fecal acetic acid concentration while the CS treatment had lower propionic acid concentration than the US treatment (p<0.05) gas emissions but decreased in fecal propionate gas emissions. Total fecal bacteria and Escherichia coli populations did not differ significantly among the treatments, while the Shigella counts were decreased (p<0.05) in synbiotics-included treatment. Fecal bacteria population was higher in the YS treatment than other treatments (p<0.05). The BS treatment had higher yeast concentration than YS, MS and CS treatments, while US treatment had higher mold concentrations than MS treatment (p<0.05). Therefore, the results of the present study suggest that synbiotics are as effective as antibiotics on growth performance, nutrient digestibility and fecal microflora composition in weaning pigs. Additionally, synbiotics from anaerobic microflora can decrease fecal noxious gas emission and synbiotics can substitute for antibiotics in weaning pigs.