• Journal of Dairy Science and Biotechnology
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• v.32 no.2
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• pp.101-104
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• 2014

Food safety is a global health goal, and food-borne disease are a significant public health threat throughout the world. Dairy products are susceptible to contamination through a wide variety of physical, microbial, and chemical hazards. Risks of microbiological hazards are of immediate and serious concern to human health. Milk was inoculated with Bacillus cereus and stored at 10, 15, 20, and $30^{\circ}C$ for 7 days. We monitored the effect of the temperature on growth rate and variance of toxin production. The growth rate of B. cereus was suppressed in low temperature. We confirmed that the growth rate and the toxin production were accelerated when the storage temperature was increased. B. cereus began to produce toxins when the number of bacteria was higher than $10^7CFU/mL$. Therefore, managing the storage temperature of milk is important to inhibit the growth and the toxin production of B. cereus.

• Journal of Dairy Science and Biotechnology
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• v.36 no.2
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• pp.106-120
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• 2018

Since 2018, the production and sales of ram-milk cheese ripened for over 60 days has been permitted in South Korea. Hence, this study aimed to examine the microbiological changes in 7 different types of Gouda cheese. During the aging period, traditional raw-milk Gouda Cheeses 1 and 2 did not contain Salmonella spp. during the 60-day storage period and no E. coli after 20-day storage. Coliform bacteria were not detected in Cheese 1 after 40 days; however, they were detected in Cheese 2 up to 60 days. Salmonella spp. were inhibited during the 60-day storage period in Cheese 3 (Salmonella spp.-contaminated raw-milk Gouda cheese), Cheese 4 (Cheese 3 contaminated with lactic acid bacteria DH 5 isolated from Kefir) and Cheese 5 (Cheese 3 contaminated with lactic acid bacteria DN1 isolated from Kefir). In particular, inhibition of Salmonella spp. was more prominent in Cheese 4 and Cheese 5 than in Cheese 3. During 60-day storage, Cheese 6 had a significantly reduced lactic acid bacteria. Furthermore, in Cheese 7, E. coli, E. Salmonella ssp. were rarely detected, and lactic acid bacteria were slightly greater in Cheese 7 than in other cheeses during the 60-day period. Moreover, all samples from Cheese 1 to Cheese 7 were not contaminated with Listeria monocytogenes, Staphylococcus aureus, Clostridium perfringens, and E. coli O157:H7.

• Food Science of Animal Resources
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• v.29 no.5
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• pp.619-626
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• 2009

As a trial for the development of a new starter culture for yogurt products, more than two hundred lactic acid bacteria strains were isolated from raw milk and healthy human feces. The strains that showed excellent growth and acid production ability in the 10% skim milk media were selected and identified as Lactobacillus casei through the API carbohydrate fermentation pattern and 16S rDNA sequence analysis. L. casei CU2604 was further investigated for its physiological characteristics as a starter culture compared with a commercial strain. The CU2604 strain showed good acid production and growth characteristics in milk, which were comparable to those of the L. casei Shirota strain. Despite the fact that both these strains displayed the same sugar fermenting pattern and PFGE band pattern, and had similar growth characteristic in milk, L. casei CU2604 exhibited different fatty acid composition in the cell wall, showed more tolerance to bile and to pH, and presented better growth inhibition activity against pathogenic bacteria. Based on these results, the L. casei CU2604 strain holds great promise for use as a novel and efficient starter culture in the production of yogurt. Additional studies on the probiotic characteristics of this strain are currently being conducted.

• Applied Biological Chemistry
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• v.48 no.1
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• pp.60-64
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• 2005

Yogurt base was prepared from skim milk added with $0.2{\sim}1.0%\;(w/v)$ chlorella powder and fermented with lactic acid bacteria (the mixed strain of Lactobacillus acidophilus, Bifidobacterium longum and Streptococcus thermophilus) at $40^{\circ}C$ for $12{\sim}18\;h$. Quality characteristics of the yogurt were evaluated in terms of acid production (pH and titratable acidity), number of viable cells, viscosity and sensory properties. The addition of chlorella powder stimulated the growth of lactic acid bacteria and remarkably enhanced the acid production. After 12 h incubation, titratable acidity of chlorella yogurt was $1.16{\sim}1.33%$ and was higher than that (1.02%) of yogurt made with only skim milk. However, the viscosity of yogurt was decreased by the addition of chlorella powder. The sensory score of yogurt added with 0.2% chlorella powder was similar to ordinary yogurt in taste and overall acceptability. When chlorella yogurt was kept at $4^{\circ}C$ for 15 days, its quality-keeping properties except for number of viable cells were relatively good. According to sensory score and storage ability, the optimum concentration of chlorella powder was around 0.2%.

• Journal of Dairy Science and Biotechnology
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• v.36 no.2
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• pp.95-105
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• 2018

Since 2018, the Korean government has permitted the production and sale of any cheese made from raw milk and aged for at least 60 days. The present study aimed to investigate the sensory characteristics of various types of Gouda cheese produced from raw milk during 60-day aging. The average pH of the raw milk used in this experiment was $6.7{\pm}0.4$, similar to that of the sterilized milk. The pH of raw-milk Gouda cheese was $5.2{\pm}0.5$ a day after the 60-day aging period, wherein the pH was $5.5{\pm}0.3$. In total, 5 samples were used for sensory evaluation in this experiment: Cheeses 1~5. With respect to flavor, Cheeses 1 and 5 received the highest and lowest scores, respectively. Raw-milk Gouda cheese produced using Salmonella spp.-contaminated raw milk was not greatly influenced by flavor; however, it had a negative effect on its appearance. In the future, it is imperative to carry out sensory evaluation of cheese produced with raw milk contaminated with various food-contaminating bacteria.

• Microbiology and Biotechnology Letters
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• v.49 no.4
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• pp.519-527
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• 2021

In this study, the hemolysis of Enterococcus faecalis BMSE-HMP strains, isolated from human breast milk, was investigated, and the anti-hemolytic and antimicrobial effects on multidrug-resistant (MDR) bacteria were investigated. The enzyme activity of E. faecalis BMSE-HMP 4 strains was measured, and it was found that the activities of esterase and esterase lipase were the highest. In addition, no hemolytic reaction was observed in any of the isolates. Subsequently, the anti-hemolytic activity against MDR strains causing hemolysis was evaluated. E. faecalis BMSE-HMP002 had the highest anti-hemolytic activity against Staphylococcus aureus CCARM 3855 at 75.71 ± 10.00%. The anti-hemolytic activity against Escherichia coli DC 2 CCARM 0238 and Pseudomonas aeruginosa CCARM 0223 showed that the activity of BMSE-HMP001 was highest at 76.92 ± 2.99% and 87.93 ± 1.93%, respectively. Examination of the antimicrobial effects against the MDR bacteria Staphylococcus spp., Escherichia spp., Pseudomonas spp., Salmonella spp., Klebsiella spp., Enterobacter spp., and E. faecalis BMSE-HMP strains showed antimicrobial effects against both gram-positive and gram-negative strains. Breastfeeding delivers enterococci into the intestinal tract of newborns by lactation, and its usefulness is attracting attention as it has been reported that enterococci have a potential effect on neonatal immune development. In this study, the hemolytic and antimicrobial effects of E. faecalis BMSE-HMP strains on MDR bacteria were investigated, to confirm their potential as useful lactic acid bacteria. Additional studies on the antibiotic resistance and toxicity of the E. faecalis BMSE-HMP strains, isolated in this study, are necessary to prove it safe for use.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.2
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• pp.306-314
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• 2003

Bio-hydrogenation of $C_{18}$-unsaturated fatty acids released from the hydrolysis of dietary lipids in the rumen, in general, occurs rapidly but the range of hydrogenation is quite large, depending on the degree of unsaturation of fatty acids, the configuration of unsaturated fatty acids, microbial type and the experimental condition. Conjugated linoleic acid (CLA) is incompletely hydrogenated products by rumen microorganisms in ruminant animals. It has been shown to have numerous potential benefits for human health and the richest dietary sources of CLA are bovine milk and milk products. The cis-9, trans-11 is the predominant CLA isomer in bovine products and other isomers can be formed with double bonds in positions 8/10, 10/12, or 11/13. The term CLA refers to this whole group of 18 carbon conjugated fatty acids. Alpha-linolenic acid goes through a similar bio-hydrogenation process producing trans-11 $C_{18:1}$ and $C_{18:0}$, but may not appear to produce CLA as an intermediate. Although the CLA has been mostly derived from the dietary $C_{18:2}$ alternative pathway may be existed due to the extreme microbial diversity in the reticulo-rumen. Regardless of the origin of CLA, manipulation of the bio-hydrogenation process remains the key to increasing CLA in milk and beef by dietary means, by increasing rumen production of CLA. Although the effect of oil supplementation on changes in fatty acid composition in milk seems to be clear its effect on beef is still controversial. Thus further studies are required to enrich the CLA in beef under various dietary and feeding conditions.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.5
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• pp.726-731
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• 2003

The aim of this research was to identify candidate probiotic lactic bacteria among indigenous dadih lactic isolates. Dadih is an Indonesian traditional fermented milk of West Sumatra which is fermented naturally. Viability of the strain is critical in determining the capacity of lactic bacteria to induce immune stimulation as well as to colonize in the intestinal tract. Therefore, LAB are proposed to exert health promoting or probiotic effects in human, such as inhibition of pathogenic microflora, antimutagenic, and the reduction of cholesterol levels. This manuscript reports in vitro probiotic properties of indigenous dadih lactic bacteria, especially some important colonization factors in GI tract, such as lysozyme, acid and bile tolerance. Bile Salt Hydrolase (BSH) activity, spectrum of bacteriocin, and antimutagenic activity of bacterial cells were also assessed. Twenty dadih lactic isolates were screened further for their tolerance to low pH, at pH 2 and 3 as well as their bile tolerance. There were ten isolates classified as acid and bile acid tolerant, and further screened for lysozyme tolerance, BSH activity. The spectrum of bacteriocin activity of isolates was assayed using cell-free neutralized supernatants by agar spot test against variety of pathogens. Lc. lactis subsp. lactis IS-10285, IS-7386, IS-16183, IS-11857 and IS-29862, L. brevis IS-27560, IS-26958 and IS-23427, Leu.mesen.mesenteroides IS-27526, and L. casei IS-7257 each has good survival rate at low pH values and in the presence of lysozyme, and short lag time in the presence of 0.3 % oxgall. Lc. lactis subsp. lactis IS-11857 and IS-29862 each has high BHS activity, Lc. lactis subsp. lactis IS-10285 and IS-16183 each had a positive spectrum of bacteriocin activity against E. coli 3301 and Lysteria monocytogenes ATCC 19112, while L. brevis IS-26958 has high BHS activity as well as positive spectrum of bacteriocin against E. coli 3301, Lysteria monocytogenes ATCC 19112, and S. aureus IFO 3060. All of the ten dadih lactic strains performed in vitro acid and bile tolerance, indicating a possibility to reach the intestine alive, and display probiotic activities.

• Journal of Dairy Science and Biotechnology
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• v.30 no.2
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• pp.139-143
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• 2012

For human including newborn baby, the intestinal microbiota can play an important role in the development of the intestinal mucosa and in maintaining the balance of the immune cells. Important functions of the intestinal microbiota include the inhibition of the colonization of the intestine by potentially pathogenic microorganisms. Thus, the research of probiotics have been focused on the prevention and treatment of disorders associated with the gastrointestinal tract (GIT), including pathogen infection, traveler's diarrhea, antibiotic-associated diarrhea, and constipation. Probiotics have also been suggested as therapeutic agents against irritable bowel syndrome and inflammatory bowel diseases. An increasing amount of evidence from clinical studies suggests that they are effective in the prevention of atopic allergies and may have potential anti-carcinogenic effects. Until recent years many scientific research for this use has been based on empirical observations. Therefore, probiotics in the form of fermented milk products have been long part of attempts to maintain good health in world wide.

• Journal of Dairy Science and Biotechnology
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• v.33 no.1
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• pp.35-46
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• 2015

Recently, much attention has been paid to the development of a value-added food category containing probiotics so as to improve human health and prevent diseases. Among various foods, the health benefits of milk and dairy products are known to humanity, and could be attributed to the bioactive components present in milk. In fermented milk products, the health benefits could be due to suitable modulation activities produced by the action of probiotic bacteria. Besides the modification of various milk components, probiotics might also act directly as preventive and therapeutic agents against some severe diseases. Probiotics promote health via their positive effects on the immune response, stimulation of natural immunity, and modulation of the production of antimicrobial peptides, cytokines, and so on. Whey proteins, a byproduct of cheese production could also have anticarcinogenic, immunostimulatory, antimicrobial, and health-promoting activities such as improving insulin sensitivity and reducing fat deposition. Therefore, milk and dairy products containing probiotics could provide various opportunities in the field of functional foods. Additionally, these functional foods may be important in the human diet and may help improve human health and prevent diseases.