• Korean Journal of Food Science and Technology
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• v.8 no.1
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• pp.6-11
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• 1976

1. Three hundred and thirty three strains of thermoduric bacteria from raw milk, H.T.S.T. sterilized milk and U.H.T. sterilized milk in the market were isolated after heat treatment at $65^{\circ}C$ for 30 minutes. 2. By microscopical and physiological examination, including the tests for proteolysis and lipolysis, the isolates were identified as 125 strains of Bacillus stearothermophilus, 69 strains as Bacillus coagulans, 57 strains as Bacillus subtilis, 76 strains as Bacillus cereus and 3 strains as Lactobacillus thermophilus. 3. The susceptibility of the selected thermoduric strains to heat, the vegetative cells of some strains in skim milk survived the heat treatment at $65^{\circ}C$ for 30 minutes or $85^{\circ}C$ for 20 minutes but not survived at $100^{\circ}C$ for 10 minutes.

• Journal of Environmental Health Sciences
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• v.8 no.2
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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%).

• Korean Journal of Veterinary Service
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• v.13 no.1
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• pp.27-31
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• 1990

This study was carried out to obtain basic data for the Improvement of microbiological quality of raw milk. Total bacterial, psychrotrophic, thermoduric and spore counts of raw milk samples taken from milk tankers in the nothern part of kyeongnam were investigated for one year from March, 1989. The result obtained were summarized as follow 1. The number of total bacteria in raw milk averaged $4.0{\times}10^6$ CFU / ml and was not affected by seasons 2. The psychrotrophic counts of raw milk averaged $1.5{\times}10^6$ CFU / ml and it was higher in winter than in summer 3. The thermoduric counts of raw milk averaged $5.8{\times}10^4$ CFU / ml and was the lowest in winter 4. The spore counts of raw milk ranging from 3-1, 880/ ml averaged 306/ ml and was the lowest in summer

• Journal of Dairy Science and Biotechnology
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• v.35 no.1
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• pp.55-72
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• 2017

The second article of 'Effects of heat treatment on the nutritional quality of milk,' titled 'Destruction of microorganisms in milk by heat treatment' and authored by Dr. Seong Kwan Cha, who worked at the Korea Food Research Institute, covers the heat-stable microorganisms that exist in milk after pasteurization. The article focusses on the microbiological quality of raw milk and market milk following heat treatment, and is divided into four sub-topics: microbiological quality of raw milk, survey and measurement of microorganisms killed in raw milk, effect on psychrophilic and mesophilic microorganisms, and effect of heat treatment methods on thermoduric microorganisms. Bacillus spp. and Clostridium spp. are sporeforming gram-positive organisms commonly found in soil, vegetables, grains, and raw and pasteurized milk that can survive most food processing methods. Since spores cannot be inactivated by LTLT (low temperature long time) or HTST (high temperature short time) milk pasteurization methods, they are often responsible for food poisoning. However, UHT (ultra high temperature) processing completely kills the spores in raw milk by heating it to temperatures above $130^{\circ}C$ for a few seconds, and thus, the UHT method is popularly used for milk processing worldwide.

• Korean Journal of Agricultural Science
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• v.14 no.2
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• pp.295-300
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• 1987

This experiment was carried out to review the chemical composition and microbiological aspects of seasonal raw milk collected from the dairy plants in Kangwon, Kyunggi, Seoul, Chungbuk, Chungnam, Jeorbuk, Jeonnam, Kyungbuk and Kyungnam of Korea. The results were summarized as follows: 1. The average composition of raw milk produced during spring season in each area showed moisture 88.00%, protein 3.49%, fat 3.43%, lactose 4.37%, and ash 0.75% but in summer it showed moisture 88.30%. protein 3.28%, fat 3.32%, lactose 4.26%, and ash 0.70%. 2. The microbiological aspects of raw milk in spring season showed viable bacteria counts $3.7{\times}10^6$, coliforms $2.2{\times}10^5$, thermoduric bacteria $1.4{\times}10^5$, thermophiles $1.4{\times}10^5$, psyclrotrophic bacteria $8.2{\times}10^5$, mould and yeast $1.9{\times}10^4$ per milliliter but in summer it showed viable bactteria counts $3.7{\times}10^6$, coliforms $2.3{\times}10^5$, thermoduric bacteria $2.3{\times}10^5$, thermophiles $7.5{\times}10$, psychrotrophic bacteria $5.0{\times}10^5$, mould and yeast $1.3{\times}10^4$ per milliliter.

• Korean Journal of Agricultural Science
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• v.9 no.2
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• pp.556-561
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• 1982

These studies were carried out to investigate the freshness and bacterial counts of ultrahigh- temperature sterilized market milk which were treated and distributed in three districts; Cheonan, Pyungtak and Suwon in Korea, and to elucidate theirs keeping qualities when stored in refregerator and at room temperature. And the results were obtained were as follows; 1. The acidities in milk from three plants after stored at $5^{\circ}C$ were retained 0.16% up to 6 weeks and 0.18% up to 10 weeks. And negative reactions were appeared for alcohol and boiling tests also up to 10 weeks. 2. After milk were stored at $25^{\circ}C$, the acidities were 0.18% up to 9 weeks and also negative reaction were appeared for both alcohol and boiling tests up to 9 weeks. 3. When milk were stored at $5^{\circ}C$, no thermoduric and coliform bacteria were detected from all samples. And the total viable number of organisms and the number of psychrophilic bacteria were $<10/m{\ell}$ for 5, 6, 7 and 10 weeks respectively. 4. Also thermoduric and coliform bacteria were not detected after milk were stored at $25^{\circ}C$ for 10 weeks. And the total viable number of organisms and the number of psychrophilic bacteria were $<10/m{\ell}$ after from 2 weeks to 10 weeks.

• Korean Journal of Food Science and Technology
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• v.52 no.2
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• pp.177-182
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• 2020

This study evaluated the effect of steam heating, gamma irradiation, and ultraviolet (UV) irradiation on microorganism reduction in order to determine an effective sterilization method for red pepper powder. The effect of each treatment on the reduction of thermoduric bacteria and total aerobic bacteria in red pepper powder were as follows: 10 kGy gamma irradiation, reduction of 4 log and 6 log CFU/g, respectively; 12 mW/㎠ UV irradiation (264 nm UV-C), reduction of less than 1 log CFU/g; steam heating at 120℃ for 40 s, reduction of approximately 2 log CFU/g. High-temperature short-time processing at 110℃ for 30 s reduced the total bacterial count in Gochujang solution from 5.70 log CFU/g to 2.26 log CFU/g; at 121℃, the solution was commercially sterile. Steam heating resulted in 1, 2, and 4 log microbial inactivation in garlic, onion, and pepper powder, respectively. Steam sterilization, which consumers prefer over other methods, may be an effective method for reducing microorganisms in spice powders, including those in red pepper powder.

• Korean Journal of Agricultural Science
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• v.20 no.2
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• pp.153-166
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• 1993

The experiments were conducted to improve raw milk quality during storage, the chemical composition and microbiological aspect of raw milk, milk thermized at $65^{\circ}C$ for 30 second, and $75^{\circ}C$ for 2 second stored at $5^{\circ}C$ for 4 days were investigated. The result obtained were summarized as follows : 1. During storage of raw and thermized milk, in the composition of milk fat, milk protein, lactose and total solid did not change significantly. 2. The range of pH and acidity for the raw milk were 6.73~5.94 and 0.16~0.27% respectively and those of the thermized milk were 6.79~6.62 and 0.16~0.17% respectively. The phosphatase test were negative in heated milk. 3. The composition of total nitrogen, NCN and whey protein were decreased, wherease those of NPN and casein were increased in heat treated milk. 4. The compositions of total nitrogen and casein were decreased as the storage period advanced, wherese those of NCN and NPN were increased. However, the composition of whey protein did not significantly change. 5. The number of coliform bacteria was not found in thermized milk. but were gradually increased in raw milk during storage period. 6. Raw milk had total bacteria count as $5.6{\times}10^6/ml$, psychrotrophic bacteria $1.8{\times}10^6/ml$ and thermoduric bacteria $1.6{\times}10^5/ml$, as the heat treatment increased microorganism counts decreased to milk thermized at $75^{\circ}C$, for 2 sec. $3.0{\times}10^3/ml$, $1.5{\times}10/ml$ and $2.7{\times}10^3/ml$ respectively. 7. The count of thermoduric bacteria, psychrotrophic bacteria and total bacteria were increased during storage period, and more rapidly increased in raw milk than in heat treated milk.

• Korean Journal of Agricultural Science
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• v.25 no.2
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• pp.181-198
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• 1998

In order to determine the optimum pasteurization conditions by microwave heating(MWH) at $50^{\circ}C{\sim}70^{\circ}C$ for 30 minute compared with water bath heating(WBH) at $65^{\circ}C$ for 30minute during storage at $5^{\circ}C$, the chemical composition, microbiological changes and keeping quality were examined and the results were as follows: 1. The fat protein lactose, total solid contents of raw milk, at $50{\sim}70^{\circ}C$ for 30 min. in MWH and at 65 for $30^{\circ}C$ min. in WBH did not changed significantly during the storage at $5^{\circ}C$. 2. The pH and acidity for the raw milk untreated were 6.75 and 0.16%, and those of MWH heated and WBH milk wee 6.75~6.50 and 0.16%~0.19%, phosphatase test were negative at $61^{\circ}C$ for 20 min. at $62^{\circ}C$ for 15 min. at $63^{\circ}C$ for 10 min. at $64^{\circ}C$ for 5 min. at $65^{\circ}C$ for 5 min. in MWH and at $65^{\circ}C$ for 30 min. in WBH. 3. Whey protein content was $18.53mg/m{\ell}$ in raw milk untreated, however, those were decreased as the heating temperature increased. The proteolytic activity of treated milk by WBH(44%) was lower than that by MWH(94%). 4. Total bacteria counts were $2.8{\times}10^5CFU/m{\ell}$ in raw milk untreated, $2.8{\times}10^3CFU/m{\ell}$ at $65^{\circ}C$ for 30 min. $2.4{\times}10^3CFU/m{\ell}$ at $70^{\circ}C$ for 30 min. in MWH and $3.0{\times}10^3CFU/m{\ell}$ at $65^{\circ}C$ for 30 min. in WBH. Because total bacteria count did not increased in MWH at $65^{\circ}C$, $70^{\circ}C$ for 30 min. and $65^{\circ}C$ for 30 min. in WBH during the 10 days storaging, Also, total bacteria counts for treated milk were a most drastic decrease after $61^{\circ}C$, $62^{\circ}C$, $63^{\circ}C$, $64^{\circ}C$, $65^{\circ}C$ for 5 min. in MWH. 5. Coliform bacteria counts were $2.6{\times}10^3CFU/m{\ell}$ in raw milk untreated. There were not detected at $55^{\circ}C{\sim}70^{\circ}C$ for 30 min. in MWH and at $65^{\circ}C$ for 30 min. in WBH. Coliform bacteria counts were not detected after $61^{\circ}C$, $62^{\circ}C$, $63^{\circ}C$, $64^{\circ}C$, $65^{\circ}C$ for 5 min. in MWH. 6. Thermoduric bacteria counts were $5.2{\times}10^4CFU/m{\ell}$ in raw milk untreated, $2.0{\times}10^3CFU/m{\ell}$ at $65^{\circ}C$ for 30 min. $1.9{\times}10^3CFU/m{\ell}$ at $70^{\circ}C$ for 30min. in MWH and $2.2{\times}10^3CFU/m{\ell}$ at $65^{\circ}C$ for 30 min. in WBH. Because thermoduric bacteria counts did not increased in MWH at $65^{\circ}C$, $70^{\circ}C$ for 30 min. and $65^{\circ}C$ for 30 min. in WBH during the 10days storaging. Also, thermoduric bacteria counts were a most drastic decrease after $61^{\circ}C$, $62^{\circ}C$, $63^{\circ}C$, $64^{\circ}C$, $65^{\circ}C$ for 5 min. in MWH. 7. Psychrotrophic bacteria counts were $2.8{\times}10^5CFU/m{\ell}$ in raw milk untreated, $2.0{\times}10^1CFU/m{\ell}$ at $65^{\circ}C$ for 30 min. $2.0{\times}10^1CFU/m{\ell}$ at $70^{\circ}C$ for 30 min. in MWH and $3.0{\times}10^1CFU/m{\ell}$ at $65^{\circ}C$for 30 min. in WBH. Because psychrotrophic bacteria counts did not increased in MWH at $65^{\circ}C$, $70^{\circ}C$ for 30min. and $65^{\circ}C$ for 30 min. in WBH during the 10 days storaging. Also, psychrotrophic bacteria counts were a most drastic decrease after $61^{\circ}C$, $62^{\circ}C$, $63^{\circ}C$, $64^{\circ}C$, $65^{\circ}C$ for 5 min. in MWH.

• Microbiology and Biotechnology Letters
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• v.13 no.4
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• pp.409-415
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• 1985

This study has been carried out in order to investigate the bacterial quality of fish meat paste products and the characteristics of isolated thermodurics from the products. Twenty samples of crab-flavored fish stick (Kematsal), 23 samples of plate fish meat paste (Panomuk, Kamaboko), 5 samples of fried fish meat paste (Tigimomuk), 2 samples of roasted fish meat paste (Puduromuk, Chikuwa), 20 samples of fish sausage were collected from processing plants and supermarkets in Pusan, Korea during the period from May to October in 1984. The results obtained are as follows. Amont the samples collected from supermarkets, roasted fish meat paste and fried fish meat paste marked hish counts in coliforms and fungi while very low in the samples of crab-flavored fish stick and plate fish meat paste. Salmonella was not detected in all the samples examined and Staphylococcus aureus was detected only in fried fish meat paste, Thermoduric bacteria were detected less than 10$^2$/g in the samples of crab-flavored fish stick and plate fish meat paste, which might come from subsidiary materials such as starch and seasonings. Among the isolated bacteria, distribution of the proteolytics were more than 87％ and the lipolytics were less than 20％. Gram positive bacteria was more than 70％ in crab-flavored fish stick and plate fish meat paste, 47.3％ in fried fish meat paste. And rod in shape was almost more than 90％ in all the samples. The most heat resistant bacterium isolated from the samples was identified as a Bacillus licheniformis(named B. licheniformis CR-11). The strain showed strong proteolytic activity and also grew well at above 2$0^{\circ}C$. The growth rate and generation time of CR-11 strain were 0.31 hr$^{-1}$ , 2.24 hr at 2$0^{\circ}C$, 0.64 hr$^{-1}$ , 1.09 hr at 3$0^{\circ}C$ and 0.78 hr$^{-1}$ , 0.89 hr at 35$^{\circ}C$. Heat resistance value of the spores of CR-11 strain suspended in phosphate buffer solution was D$_{85}$ $^{\circ}C$=41.9 min, D$_{90}$ $^{\circ}C$=27.9 min, D$_{95}$ $^{\circ}C$=10.2 min, D$_{100}$ $^{\circ}C$=4.3 min (Z=13.8$^{\circ}C$)