• 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%).

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.2
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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.

• Food Science of Animal Resources
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• v.18 no.3
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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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• v.18 no.1
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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.

• The Korean Journal of Food And Nutrition
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• v.7 no.3
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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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• v.19 no.1
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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.

• Korean journal of food and cookery science
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• v.13 no.3
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• pp.293-298
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• 1997

The changes of microorganisms, pH, color and flavor were examined in the chicken treated with O％, 1%, 2%, and 3% lactic acid solutions during the storage at 4$^{\circ}C$. Lactic acid treatment inhibited the growth of mesophiles, psychrotrophs, and enteric bacilli as the concentration increased, however, it was not effective on yeasts and molds. Extension of lag phase for mesophilic bacteria and suppression of log phase for psychrotrophs and enteric bacilli were observed in the growth inhibition patterns. The pH of the chicken increased during the storage and antimicrobial effect of lactic acid appears to be due to mainly the decrease of pH. No flavor change of the chicken was observed by any lactic acid treatment, however, 3％ lactic acid caused discoloration of the chicken.

• Korean Journal of Veterinary Service
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• v.22 no.4
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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.

• Korean Journal of Food Science and Technology
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• v.23 no.4
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• pp.452-458
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• 1991

Psychrotrophs producing protease were isolated during ripening periods of Cheddar cheese and one of them containing the highest protease activity was identified as Pseudomonas fluorescens 65. The extracelluar proteolytic enzyme was partially purified from P. fluorescens 65 through the Sephadex G-100 gel filtration. The protease was eluted between 190 ml and 230 ml of elution volume of sodium phosphate buffer. The purified protease showed a single band in SDS-PAGE and its molecular weight was 47,000. The composition of amino acid for the protease was determined and the most abundant amino acids were glutamic acid (14.96%) and serine (13.86%). The optimum temperature and pH for the activity was $45{\sim}50^{\circ}C$ and 6.0, respectively.

• Korean Journal of Food Science and Technology
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• v.26 no.6
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• pp.764-769
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• 1994

This study was performed to obtain fast, consistant and reliable estimation system of bacterial counts of raw milk, which effectively related to the quality of sanitaion and the condition of production at the farm. This study compared regression equation and correlation coefficient relationship between standard plate counts and data of Malthus conductance method for the detection time of total, psychrotrophs, coliform bacterial counts in raw milk. Regression equation (RE) between conductance detection time (Y) and total bacterial log counts (X) was Y=18.27651 - 2.07550X, with correlation coefficient -0.95(n=201). In coliform, RE was Y=9.320848 - 1.15598X with correlation coefficient -0.90 (n=207). Psychrotrophs had the RE of Y=29.96008-3.02487 with correlation coeffecient -0.9 (n=201). This conductance method gave results more quickly and was less labor-intensive than traditional standard plate count method.