• 한국환경보건학회지
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• 제8권2호
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• pp.47-51
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• 1982

135 Raw milk samples corrected from 4 dairy plants before processing were held at 63$\circ$C for 30 minutes and 80$\circ$C for 10 minutes. Thermoduric mesophiles, psychrotrophs and thermophilic bacteria were estimated from the samples treated at 63$\circ$C for 30 minutes and aerobic spore formers from the samples treated at 80$\circ$C for 10 minutes. The results obtained were as follows. 1) The distribution of thermoduric mesophiles were $10^4 - 10^5$ cfu/ml (45.2%), $10^2 - 10^4$ cfu/ml (21.5%), $10^5$ cfu/ml over (20.7%), $10^2 - 10^3$ cfu/ml (8.9%) and $10 - 10^2$ cfu/ml (3.7%). 2) The distribution of thermoduric psychrotrophs were 10 - $10^2$ cfu/ml (40.2%), $10^2 - 10^3$ cfu/ml (29.5%), 10 cfu/ml below (22.3%) and $10^3 - 10^4$ cfu/ml (8.0%). Isolated psychrotrophs had the characteristics of Streptococcus, Micrococcus and Alcaligenes group. 3) The distribution of thermophilic bacteria were 10 cfu/ml below (91.9%), and 10 - $10^2$ cfu/ml (81.8%). 4) Aerobic spore formers counts were 10 cfu/ml below (27.4%), $10^3 - 10^4$ cfu/Illl (26.5%), $10^2 - 10^3$ cfu/ml (23.9%)and 10 - $10^2$ cfu/ml (22.1%).

• Asian-Australasian Journal of Animal Sciences
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• 제19권2호
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• pp.292-296
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• 2006

Meat marination has been applied to improve product's physical and sensory attributes for years, but usually it is not intended to improve microbial quality of the product. Tumbling, which helps the distribution of marinade solution during processing, should enhance the action of antimicrobial agents. The objective of this study is to evaluate the combined effects of nisin, tumbling and storage time on total microflora and psychrotrophs counts on poultry. A marinade that contained acetic acid (1%) and salt (3%) with pH adjusted to 4 was developed as a standardized marinade. Drumsticks were marinated with various nisin levels (0, 50, or 100 IU/ml) combined with tumbling (0, 10, or 20 min), and then stored at $4^{\circ}C$ for 18 h. The total microflora and psychrotrophs counts of the samples were evaluated after 0, 2, 4, and 7 days of storage. The results indicated that at a given storage time, the samples tumbled for either 10 or 20 min had significantly (p<0.05) lower microbial counts when compared with the samples without the tumbling treatment. The microbial counts of the tumbled samples increased as storage time increased. Microbial counts significantly (p<0.05) decreased when more nisin was increased up to the level of 100 IU/ml. In conclusion, adding of nisin at the level of 50 IU/ml with tumbling for 10 min decreased the total microflora and psychrotrophs counts of the marinated chicken broiler drumsticks.

• 한국축산식품학회지
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• 제18권3호
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• pp.232-239
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• 1998

This experiment was conducted to investigate radurization effects of gamma ray and electron beam irradiation at 1.5 and 3.0 kGy on beef steaks during 8 days of storage at 5$^{\circ}C$. Total bacteria count, psychrotrophs, mesophiles and thermophiles were analyzed at 2 days intervals. Nonirradiated beef steak was used a scontrol Total bacteria counts, psychrotrophs, mesophiles and thermophiles of the control samples showed 3.03∼4.72 logCFU / g at 0 day and increased to 7.67∼10.90 logCFU / g during 8 days storage except thermophiles. Total bacteria counts, psychrotrophs and mesophiles of beef steaks at 8 days were significantly (p＜0.05) decreased to 3.61∼5.43 logCFU / g by gamma ray and to 3.83∼7.02 logCFU / g by electron beam irradiation at 1.5 and 3.0 kGy. Thermophiles of all irradiated samples at any dose were not detectable through 8 days storage. These results suggested that both gamma ray and electron beam irradiation were effective to extend lag phase of bacterial growth of refrigerated beef. Gamma ray irradiation was better than electron beam irradiation in terms of radurization effects of beef.

• Journal of Dairy Science and Biotechnology
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• 제18권1호
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• pp.38-46
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• 2000

Since generalization of cold storage of raw and processed milk, psychrotrophic bacteria has become more important. The number present in raw milk is related to sanitary conditions during pro-duction and to length and temperature of storage before pasteurization. Growth of psychrotrophs In raw milk often reduces the quality of pasteurized products. Recently, some pathogenic bacteria like Listeria monocytogenes, Yersinia enterocolitica, Bacillus cereus are reported to grow at low temperature and cause food poisoning. The presence of gram positive psychrotrophic bacteria which can survive pasteurization can limit the shelf life of pasteurized milk during extended storage and the survival of heat stable proteases and lipases produced by gram negative psychrotrophic bacteria often brings about proteolytic damage to milk protein in the products. Therefore, in order to prevent the deteorioration of milk and milk products by the growth of psychrotrophs, it is necessary to cool down the temperature of raw milk as soon as possible after milking and to keep the temperature below 5t during storage at farm. As psychrotrophic bacteria become readily predominant in raw milk under refregeration, it can be considered to change the traditional incubating temperature for SPC from 30${\sim}$32$^{\circ}C$ to 25${\sim}$27$^{\circ}C$ at which the psychrotrophs prefer to grow. The psychrotrophic bacterial count(PBC) is of limited use in dairy industry, because of the 10 days incubation period. Although estimates of psychrotrophic bacteria may provide an acceptable shelf-life prediction, there is no single, generally acceptable rapid method for replacing the PBC at the moment. Consequently, faster method for esmating psychrotrophic bacteria has to be developed.

• 한국식품영양학회지
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• 제7권3호
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• pp.203-212
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• 1994

The nangmyun is a Korean iced noodle made by putting buckwheat-noodles into cold broth. Seven samples of nangmyun-broths were collected from Korean restaurants in Bucheon during July 1994. The contamination levels of nangmyun-broths by coliform bacteria were determined, and then the 40 colonies of coliform bacteria, isolated randomly from 4 samples of nangmyun-broths, were identified at genus or species level with the additional test for psychrotrophic character The coliform counts in nangmyun-broths were 6.0x102-6.5$\times$104/ml(average 2.3$\times$104%). Among the 40 strains of isolates, 27 strains(67.5%) were identified as the genus Klebsiella, 9 strains(22.5%) as the genus Enterobacter, 2 strains(5.0%) as the genus Citrobacter and 2 strains (5.0%) as the genus Escherichia. Among 27 strains of Klebsiella, 11 strains (40.8%) were identified as K planticola, 4 strains(14.8%) as K. pneumoniae, 2 strains(7.4%) as K. ozaenae and 2 strains(7.4%) as K. terrigena, but 8 strains(29.6%) of a typic\ulcorner1 Klebgiella could not be Identified at species level. All the 40 strains of coliform bacteria were psychrotrophs showing slow growth at 1$0^{\circ}C$, and 18 strains(45%) grew at 5$^{\circ}C$. It was thought to be a good basic data In describing the reason for too high coliform counts in nangmyun-broths that all coliform bacteria tested In this study were psychrotrophs.

• Asian-Australasian Journal of Animal Sciences
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• 제19권1호
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• pp.109-112
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• 2006

The objective of this study was to evaluate the combined effects of lactoperoxidase system (LPS), thermal treatment and storage time on total microflora and psychrotrophs counts of the marinated broiler drumsticks. A marinade that contained acetic acid (1%) and salt (3%) with pH adjusted to 4 was developed as a standardized marinade. Drumsticks were marinated with various LPS levels, combined with thermal treatment (4 or $58^{\circ}C$ for 2 min), and then stored at $4^{\circ}C$ for 18 h. The microbial counts of the samples were measured after 0, 2, 4 and 7 days of storage for drumsticks held at $4^{\circ}C$. The results indicate that adding LPS at the level of 1 unit ($1{\mu}g/ml$ LP, 5.9 mM KSCN, and 2.5 mM $H_2O_2$) significantly (p<0.05) decreased the total microflora and psychrotrophs counts of the marinated broiler drumsticks. In addition, samples treated with a thermal treatment ($58^{\circ}C$ for 2 min) had significantly (p<0.05) lower microbial counts when compared with the control.

• 한국식품조리과학회지
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• 제13권3호
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• pp.293-298
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• 1997

닭고기를 멸균한 증류수, 1%, 2%, 3% 젖산용액으로 처리하여 4$^{\circ}C$에서 보관하면서 미생물 수의 변화, pH의 변화, 색과 냄새의 변화를 조사하였다. 중온성균, 저온성균, 장내세균에 대해서는 젖산의 농도가 높아질수록 성장억제 효과가 증가하였고, 효모와 곰팡이에 대한 젖산의 성장억제 효과는 높지 않은 것으로 나타났다. 성장억제는 중온성균에서는 유도기가 연장되고, 저온성균에서는 대수기가 억제되는 형태로 나타났다. 저장기간 중 닭고기의 pH는 상승하였고, 젖산의 항미 생물효과는 주로 pH 저하에 의한 것으로 추정되었다. 3%까지의 젖산용액은 닭고기의 냄새에 유의적인 변화를 일으키지 않았으며, 1%와 2% 젖산용액은 닭고기의 색에 변화를 주지 않았으나, 3% 젖산용액은 탈색을 일으켰다.

• 한국동물위생학회지
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• 제22권4호
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• pp.411-418
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• 1999

In this studies, the ability of chlorine and lactic acid to reduce bacterial population of the pathogenic microorganisms were examined on artificially inoculated chicken skin. About 10$^{5}$ cells of staphylococcus aureus, salmonella enteritidis, listeria monocytogenes and escherichia coli O157:H7 were inoculated in chicken skin. The contaminated samples were washed for 1 min with sodium hypochlorite solutions that contained 2, 5, 10, 20 and 50mg/$\ell$ available chlorine and counted number of the agents. Viable population were no significantly difference (p$\geq$0.05) between concentration of chlorine and strains of the pathogens. In the samples inoculated with pathogens were washed in 20mg/$\ell$ chlorine and then stored at $^5{\circ}C$ for up to 10 days, the initial counts of psychrotrophs and aerobic plate counts were 4.02 to 4.36 log cfu/$\textrm{cm}^2$ and increased slightly in course of time. But 10 days after, the pathogens were a little reduced from 3.66~4.91 log cfu/$\textrm{cm}^2$ to 2.54~4.66 log cfu/$\textrm{cm}^2$. In the case of washed skin with solution of 20mg/$\ell$ chlorine and 0.5% lactic acid then store at $^5{\circ}C$ for up to 10 days, population of psychrotrophs and aerobic plate counts on chicken skin were markedly reduced immediately after treatment, but the numbers of contaminants were slightly increased after 6 and 8 days. Specifically, numbers of St aureus, S enteritidis, L monocytogenes and E coli O157:H7 were reduced to 0.5, 0.4, 0.3 and 1.15 log cfu/$\textrm{cm}^2$ after 10 days of storage, respectively, on aerobic plate counts.

• 한국식품과학회지
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• 제23권4호
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• pp.452-458
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• 1991

체다치즈 숙성기간 중 존재하는 저온성세균을 분리하여 단백질분해능이 우수한 균주를 선발하였고 이 선발된 균주가 생산하는 효소의 특성을 연구하였다. 체다치즈 숙성기간 중 미생물의 변화를 관찰한 결과 내냉성세균이 일정하게 유지되고 있었는데 그 중 200개의 균주를 1차 선발한 후 단백질분해능이 우수한 균주 3개를 분리, 동정한 결과 P. fluorescens 두 종과 A. denitrificans였다. 그 중 활력이 가장 높은 P. fluorescens 65가 생산하는 효소를 gel filtration에 의해 정제한 결과 $190{\sim}230ml$ elution volume에서 protease가 용출되었고 SDS-PAGE로 분석한 결과 분자량은 47,000인 것으로 나타났으며 아미노산 조성은 Glu(14.96%)와 Ser(13.83%)의 함량이 제일 높았고 Met, Trp은 존재하지 않았다. P. fluorescens 65의 성장곡선에 따른 효소활력을 실험한 결과 세포증식이 활발한 대수증식기에서 단백질분해효소를 많이 분비함이 나타났으며 pH는 변화가 없이 일정하였다. Extracellular protease 65의 반응 최적온도는 $45{\sim}50^{\circ}C$ 사이었으며 최적 pH는 6.0으로 나타났다.

• 한국식품과학회지
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• 제26권6호
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• pp.764-769
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• 1994

본 실험은 원유내외 세균을 빠르고, 일관성있고, 신뢰성이 있는 평가 system을 얻기 위함이며, 원유 내외 총균수와 저온성균수, 대장균군수를 malthus의 detection time과 regression equation과 상관관계를 조사하였다. Conductance method는 종래의 plate count method보다빠르고 자동적이며, 노동력을 최대한 절감할 수 있다. 그 결과는 다음과 같다. 1. Conductance detection time을 (Y), total bacterial log count를 (X)라고 할 때 regression equation Y=18.27651-2.07550X, 상관계수는 -0.95(n=201)로 나타났다. 2. Conductance detection time을 (Y), total bacterial log counts를 (X)라고 할때 regression equation Y=9.32048-1.15598X, 상관계수는 -0.90(n=207)로 나타났다. 3. Conductance dotection time을 (Y), psychrotrophic bacterial log counts를 (X)라 할때 regression equation Y=29.96008-3,02487X 상관계수는 -0.90(n=201)로나타났다.