• Food Science of Animal Resources
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• v.44 no.2
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• pp.372-389
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• 2024

This study investigated the efficacy of ultraviolet-C (UV-C) irradiation in enhancing the quality of raw bovine milk by targeting microbial populations and lipid peroxidation, both of which are key factors in milk spoilage. We categorized the raw milk samples into three groups based on initial bacterial load: low (<3 Log 10 CFU/mL), medium (3-4 Log 10 CFU/mL), and high (>4 Log 10 CFU/mL). Using a 144 W thin-film UV-C reactor, we treated the milk with a flow rate of 3 L/min. We measured the bacterial count including standard plate count, coliform count, coagulase-negative staphylococci count, and lactic acid bacteria count and lipid peroxidation (via thiobarbituric acid reactive substances assay) pre- and post-treatment. Our results show that UV-C treatment significantly reduced bacterial counts, with the most notable reductions observed in high and medium initial load samples (>4 and 3-4 Log 10 CFU/mL, respectively). The treatment was particularly effective against coliforms, showing higher reduction efficiency compared to coagulase-negative staphylococci and lactic acid bacteria. Notably, lipid peroxidation in UV-C treated milk was significantly lower than in pasteurized or untreated milk, even after 72 hours. These findings demonstrate the potential of UV-C irradiation as a pre-treatment method for raw milk, offering substantial reduction in microbial content and prevention of lipid peroxidation, thereby enhancing milk quality.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.11
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• pp.1643-1650
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• 2017

Objective: The control of psychrotrophic bacteria causing milk spoilage and illness due to toxic compounds is an important issue in the dairy industry. In South Korea, Gangwon-do province is one of the coldest terrains in which eighty percent of the area is mountainous regions, and mainly plays an important role in the agriculture and dairy industries. The purposes of this study were to analyze the indigenous microbiota of raw milk in Gangwon-do and accurately investigate a putative microbial group causing deterioration in milk quality. Methods: We collected raw milk from the bulk tank of 18 dairy farms in the Hoengseong and Pyeongchang regions of Gangwon-do. Milk components were analyzed and the number of viable bacteria was confirmed. The V3 and V4 regions of 16S rRNA gene were amplified and sequenced on an Illumina Miseq platform. Sequences were then assigned to operational taxonomic units, followed by the selection of representative sequences using the QIIME software package. Results: The milk samples from Pyeongchang were higher in fat, protein, lactose, total solid, and solid non-fat, and bacterial cell counts were observed only for the Hoengseong samples. The phylum Proteobacteria was detected most frequently in both the Hoengseong and Pyeongchang samples, followed by the phyla Firmicutes and Actinobacteria. Notably, Corynebacterium, Pediococcus, Macrococcus, and Acinetobacter were significantly different from two regions. Conclusion: Although the predominant phylum in raw milk is same, the abundances of major genera in milk samples were different between Hoengseong and Pyeongchang. We assumed that these differences are caused by regional dissimilar farming environments such as soil, forage, and dairy farming equipment so that the quality of milk raw milk from Pyeongchang is higher than that of Hoengseong. These results could provide the crucial information for identifying the microbiota in raw milk of South Korea.

• Korean Journal of Veterinary Service
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• v.19 no.1
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• pp.39-45
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• 1996

Sulfonamides are widely used to treat mastitis of cattle in field. The study was carried out to analyze sulfonamid residues In raw milk from south Kyeonggi area. The milk sample was deproteinated with acetone and defatted with hexane. The residual sulfonamides were extracted with ethylacetate, concentrated under vaccum, reconstituted with the acetate buffer-methanol mixture, reacted with fluorescamine, and then analyzed by HPLC-fluorescence detector(EX. 39nm, Em. 495nm) with methanol : acetate buffer system(3/2, v /v) as a mobile phase. The results analyzed by Thin layer chromatography and High performance liquid chromatography were summarized as follows. 1. A total of 24 cases out of 478 raw milk samples(5.0%) collected during April and May showed positive reaction to sulfonamide residues. Among 24 positive reactors, 9 cases were positive to sulfanilamides(32.1%), 8 cases were positive to sulfathiazoles(28.6%) and 5 cases were positive to sulfamonomthoxines (7.9%) , respectively. 2. During July and August, 31 cases out of 464 raw milk samples(6.7%) showed positive re action to sulfonamide residues. Among them S cases were positive to sulfanilamides, 5 cases sulfathiazoles and 5 cases sulfamonomethoxines(16.1%), respectively.

• 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.

• Journal of Dairy Science and Biotechnology
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• v.24 no.2
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• pp.11-20
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• 2006

Korea dairy industry has a long and chronic problems to consume raw milk , those are surplus milk and decline the market milk consumption continued about 10 years. This study was aim to propose and to find the solution for dairy industry problems. After WTO system, with the importation of dairy products, domestic milk production has fell into the situation of excess supply and huge inventory of dried milk, the milk powder stocks have increased since 2002. That made a chronic decline milk consumption in Korea. The core of chronic problem of Korea dairy industry is the decreasing in market milk consumption. If they have a settlement of any other way using their raw milk to process and consumption to market milk, there will be a solution to solve the chronic problems in this situation. Especially, that will be a development of small farm scale natural cheese production and consume. This may be lead a situation of increase the raw milk consumption, because natural cheese making needs much of raw milk more than market milk. But there are very low technical level of farmers cheese making status, so they need a cheese making educational program for their commercial level of cheese products. Under these situation, there are needed a way out of educational system for the dairy farmers to obtain the high level of cheese making technology from the trustable and scientific organization. The natural cheese making technique of dairy farmers should be accumulated to get the consumers' solid recognition of high quality of natural cheese as LOHAS(Lifestyle Of Health And Sustainability) foods.

• Journal of Dairy Science and Biotechnology
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• v.37 no.1
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• pp.33-39
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• 2019

The purpose of this study was to explore the microbiological safety of various cheeses made from raw milk currently imported and sold in Korea. A total of 12 cheeses were considered for the study - 4 kinds of imported cheese made from raw milk, 4 kinds of imported cheese made from pasteurized milk, and 4 kinds of domestic cheese made from pasteurized milk, and aerobic count, presence of E. coli, Salmonella spp., and Listeria monocytogenes were investigated. Results from this study showed that in the 12 different kinds of cheese tested, E. coli, Salmonella spp., and Listeria monocytogenes were negative. Therefore, the sanitary conditions of imported cheese made from raw milk, imported cheese made from pasteurized milk, and domestic cheese made from pasteurized milk are considered safe. The mean aerobic count in the 12 types of tested cheese was below 4.0 log CFU/g. In conclusion, various cheeses produced from raw milk or pasteurized milk currently sold in Korea have been found to be hygienic and safe. In the future, raw milk cheeses produced and sold in Korea will require long-term research not only to ensure safety but also to produce new, high-quality products.

• Journal of Nutrition and Health
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• v.28 no.2
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• pp.144-151
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• 1995

This study investigates the supplementing effects of milks by various heat treatment on growth performance and protein and calcium metabolism of rats. For 4 weeks, raw, LTLT-HTST-and UHT-processed milks were given to rats which fed on a calcium free, semi-synthetic diet containing 5%casein. There were no significant differences among the experimental groups in weight gain, feed efficiency ratio and the serum level of total protein and calcium. Also, no significant differences were showed in protein efficiency, nitrogen balance, apparent protein digestibiltiy and the contents of weight and calcium of the left femur as well as 2 incisors. However, the biological value of protein in the UHT-milk group was significantly higher than that of the raw-milk group. The apparent calcium digestibility and calcium balance in the UHT-milk group were higher than those in the raw-, LTLT- and HTST-milk groups. The weight of left femur in all the groups supplemented with various heat-treated milks was significantly impair the nutritive value of protein and calcium in milk. Futhermore, UHT-processing may improve the bioavailability of protein and calcium in milk.

• Korean Journal of Veterinary Research
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• v.39 no.3
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• pp.609-615
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• 1999

From July of 1997 to June of 1998, total 279 raw milk samples over withdrawal period after mastitis treatment from dairy farms located in the provinces of Kyonggi and Choongchung were collected to test drug residues. Each sample was tested by TTC- II test and Delvotest SP. Among the total 152 raw milk samples of cow treated by ${\beta}$-lactams, 32 samples(21.2%) were positive on the Delvotest and 15 samples(9.9%) showed positive on the TTC-II test. Also, from the total 37 samples treated by sulfonamides, 5 samples(13.5%) were positive on the Delvotest and 3 samples(8.1%) showed positive on the TTC-II test. For the total 55 raw milk samples of cow treated by tetracyclines, 9 samples(16.4%) were positive on the Delvotest and 5 samples(9.1%) showed positive on the TTC-II test. In addition, from the total 35 samples treated by aminoglycosides, 7 samples(20.0%) were positive on the Delvotest and 5 samples(14.3%) showed positive on the TTC-II test. Our study shows that it is possible that drugs are to be detected by the drug residues test of an individual raw milk even over the withdrawal period after mastitis treatment and the raw milk of bulk tank.

• Journal of agriculture & life science
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• v.46 no.1
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• pp.189-194
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• 2012

Measurement of compositions and somatic cells in raw milk by chemical methods usually requires a lot of time, skilled labor and expensive analytical equipments. Recently, near-infrared reflectance spectroscopy (NIRS), which is a rapid, cost-effective and non-destructive technique, has been extensively used for safety and quality evaluation in the field of dairy products. However, less study has been performed to evaluate the effect of transmitted light on milk quality during NIRS analysis. Therefore, the objective of this study was to analyze the changes in milk quality using transmitted light. Raw milk samples collected from dairy farm from Siga prefecture in Japan were analyzed for fat, protein, lactose, solids not fat, total solids, milk urea and citric acid using the Milko scan 4000. Somatic cells in raw milk samples were counted by the Fossomatic 5000. Transmittance spectra of 50 ml raw milk samples were obtained by the Lax-Cute lighter in the 400 nm or less, 689 nm, 773 nm, 900 nm and 979 nm. As a result, milk fat as well as somatic cell count was increased by 2.6% and 9.0%, respectively. The other compositions were, however, changed within the relative error of the measurement. Further studies are needed to apply raw milk quality evaluation using the UV band by accumulating more samples and more data.

• Journal of Dairy Science and Biotechnology
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• v.31 no.1
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• pp.21-33
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• 2013

The purpose of this study was to improve the production of Mozzarella cheese analogues manufactured using mixtures of soy milk and concentrated raw milk by performing ultrafiltration (UF) and to assess the quality of these cheeses during a 30-day storage period at $4^{\circ}C$, relative to that of Mozzarella cheese manufactured with the traditional method. The solid consistency of Mozzarella cheese analogue prepared from milk mixtures was lower than that of cheese manufactured from raw milk or soy milk and increased during storage, which is considered to be the result of decreasing water levels, as well as with increasing soy milk concentrations. In the Mozzarella cheese analogue generated using the milk mixtures, the fat content decreased with increase in the soy milk concentration, while it decreased during the storage period. Lactose levels were lowest in cheese composed of soy milk or raw milk and processed by UF, and decreased during storage in cheese produced using milk mixtures. In milk mixtures containing soy milk, the protein concentration increased with increasing amounts of raw milk and did not change during the storage period. The water-soluble nitrogen compound level was similar between cheeses and increased only slightly during storage. The amount of non-protein nitrogen compounds was higher in the cheese analogue than in the control cheese and tended to increase during storage. Analysis of the physicochemical traits of the Mozzarella cheese analogue yielded the following results: During storage, titratable acidity levels increased while pH tended to decrease. After analysis using electropherograms, it was classified as ${\alpha}$-, ${\beta}$-, or ${\kappa}$-casein. The results of rheometry tests showed that in the Mozzarella cheese analogue prepared from milk mixtures, with raw milk concentrated by UF, increases in concentration rate lead to lowered hardness, elasticity, cohesiveness, and brittleness. When cheese was produced from milk mixtures and concentrated by UF, meltability increased as the concentration rate increased, although to an extent that was less than that observed for the control cheese, and tended to increase during storage. Sensory evaluation showed that the analogue cheese was much better than the control cheese in terms of formation, appearance, and flavor.