• 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.

• Food Science of Animal Resources
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• v.23 no.4
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• pp.327-332
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• 2003

This study was conducted to investigate the characteristics of strains which were isolated from market milk treated with ESL(extended shelf life) and conventional system, and to compare the microbiological quality of ESL milk with conventional milk. In order to characterize the isolated strains, purification, Gram staining, spore staining, catalase, oxidase, motility test, and identification by means of automatic identificator were performed. The results obtained are as follows: total 364 selected strains were analyzed in this study. Depending upon the isolated source, the number of strains from conventional milk was found to be Higher than ESL-milk. By means of grouping of total strains, Bacillus ssp. and Staphylococcus ssp. showed to be predominant. But most of strains were distributed with various groups except Lactobacillus ssp. When the isolates were compared with milk process methods, Enterococcus ssp. was detected much on market milk treated with LTLT pasteurization. Also, Pseudomonas ssp. was detected much on conventional milk treated with UHT pasteurization. By comparison with genus groups depending upon storage temperature of market milk, the higher milk storage temperature increased, the most frequency detected Bacillus ssp. increased. Also, Pseudomonas ssp. was detected most frequently at 10$^{\circ}C$ storage condition. Generally this genus derived from post-contamination during milk processing and related to the quality of market milk during chilled system. In conclusion, it was shown that ESL system reduced post-contamination during milk process, following the improvement of product quality and life cycle during the distribution of market milk.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.7
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• pp.1017-1025
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• 2000

The traditional methods for determining the quality of milk, cheese and meat are tedious and expensive, with a significant wastage of chemicals which pollute the environment. To overcome these disadvantages, the potential of near infrared spectrophotometry (NIR) for monitoring the quality of milk and meat has been evaluated by a number of researchers. While most studies indicate that NIR can be used to predict chemical composition of milk and meat, and to monitor the cutting-point during cheese manufacturing, one study demonstrated the potential of NIR to predict sensory characteristics (e.g. hardness and tenderness) of beef. These calibrations were developed on a small number of samples, limiting their value for adoption by the industries. Now that the sophisticated computer software is available, more robust calibrations need to be developed to monitor both chemical and physical characteristics of meat and meat products simultaneously.

• Journal of the Korean Dietetic Association
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• v.20 no.2
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• pp.77-86
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• 2014

This study was carried out to evaluate the effects of stevia (Stevia rebaudiana Bertoni) leaf powder on soybean milk quality. Soybean milk was prepared with the addition of 0.1 g (SP1), 0.2 g (SP2), 0.3 g (SP3), 0.4 g (SP4) of stevia leaf powder. The pH of soybean milk added with stevia leaf powders ranged from 7.90 to 7.98, whereas that of control was 7.88. The viscosity of soybean milk added with stevia leaf powder was 11.13~12.71 cp while that of control was 11.09 cp. Soymilk added with stevia leaf powder yielded values of Hunter L (59.40~64.94), a (-7.63~-6.45), and b (18.71~19.63), whereas that of control were 67.45, -4.74 and 20.13, respectively. There was decrease upon addition of stevia leaf powder. During storage, the pH, viscosity, L, and b values were decreased continuously. According to sensory evaluation, taste, and flavor of SP3 were better than the other groups. Quality characteristics between control and SP3 showed no significant differences. Therefore, this study showed the possibility of substituting 0.3 g of stevia leaf powder instead of sugar for creating a standard quality soybean milk with low calories. Upon the results of this study, it may be assumed that there are consequences positive responses to health-oriented consumers when using stevia leaf powder.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.8
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• pp.1207-1213
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• 2016

Heat stress negatively affects milk quality altering its nutritive value and cheese making properties. This study aimed at assessing the impact of seasonal microclimatic conditions on milk quality of Friesian cows. The study was carried out in a dairy farm from June 2013 to May 2014 at Beni-Suef province, Egypt. Inside the barn daily ambient temperature and relative humidity were recorded and used to calculate the daily maximum temperature-humidity index (mxTHI), which was used as indicator of the degree of heat stress. The study was carried out in three periods according to the temperature-humidity index (THI) recorded: from June 2013 to September 2013 (mxTHI>78), from October 2013 to November 2013 (mxTHI 72-78) and from December 2013 to April 2014 (mxTHI<72). Eighty Friesian lactating dairy cows were monitored in each period. The three groups of cows were balanced for days in milk and parity. Milk quality data referred to somatic cell count, total coliform count (TCC), faecal coliform count (FCC), Escherichia coli count, percentage of E. coli, and Staphylococcus aureus, percentage of fat, protein, lactose, total solid and solid non-fat. Increasing THI was associated with a significant decrease in all milk main components. An increase of TCC, FCC, and E. coli count from mxTHI<72 to mxTHI>78 was observed. In addition, the isolation rate of both S. aureus and E. coli increased when the mxTHI increased. The results of this study show the seriousness of the negative effects of hot conditions on milk composition and mammary gland pathogens. These facts warrant the importance of adopting mitigation strategies to alleviate negative consequences of heat stress in dairy cows and for limiting related economic losses.

• Journal of Dairy Science and Biotechnology
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• v.36 no.1
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• pp.49-71
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• 2018

Heat treatment is the most popular processing technique in the dairy industry. Its main purpose is to destroy the pathogenic and spoilage bacteria in order to ensure that the milk is safe throughout its shelf life. The protease and lipase that are present in raw milk might reduce the quality of milk. Plasmin and protease, which are produced by psychrotrophic bacteria, are recognized as the main causes of the deterioration in milk flavor and taste during storage. The enzymes in raw milk can be inactivated by heat treatment. However, the temperature of inactivation varies according to the type of enzyme. For example, some Pseudomonas spp. produce heat-resistant proteolytic and lipolytic enzymes that may not be fully inactivated by the low temperature and long time (LTLT) treatment. These types of enzymes are inhibited only by the high temperature and short time (HTST) or ultra-high temperature (UHT) treatment of milk.

• Food Science and Industry
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• v.53 no.3
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• pp.256-263
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• 2020

Milk pasteurization is used to destroy harmful bacteria present in the raw milk for improvement of the keeping quality of dairy products. It is generally carried out in dairy industries as the heating process of raw milk in properly designed and operated equipment to a specific temperature for a specified a specified period. However, thermal processing may cause quality changes in milk as well as significant nutritional losses. Hence, many researchers have started work to design alternative strategies to produce safer foods with minimal thermal treatments for pasteurization. Therefore, the present paper shows the current status of commercial pasteurization system of dairy products in korean industry and the research efforts carried out by researchers on novel milk pasteurization system that could be an alternative to traditional thermal processes for maintaining the freshness of dairy products.

• Analytical Science and Technology
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• v.35 no.1
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• pp.8-14
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• 2022

Many studies have shown that advanced glycation end-products (AGEs) and glycation adducts are significantly linked to aging and disease. Particularly, the level of glycation in human milk is important because the AGE intake is closely related to AGE levels in infants. In this study, we used human milk samples obtained from four primiparae and four multiparae. We isolated proteins using acetone and trichloroacetic acid (TCA) precipitation. A total of 67 glycated proteins and 122 glycated peptides was quantified; among them, 19 glycated peptides were differentially expressed. We confirmed that the degree of glycation differed according to fertility. The study provides a foundation for using proteomics to evaluate the mother's milk quality and link between maternal health and human milk quality.

• 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.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.7
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• pp.1022-1028
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• 2016

Milk composition is an imperative aspect which influences the quality of dairy products. The objective of study was to compare the chemical composition, nitrogen fractions and amino acids profile of milk from buffalo, cow, sheep, goat, and camel. Sheep milk was found to be highest in fat ($6.82%{\pm}0.04%$), solid-not-fat ($11.24%{\pm}0.02%$), total solids ($18.05%{\pm}0.05%$), protein ($5.15%{\pm}0.06%$) and casein ($3.87%{\pm}0.04%$) contents followed by buffalo milk. Maximum whey proteins were observed in camel milk ($0.80%{\pm}0.03%$), buffalo ($0.68%{\pm}0.02%$) and sheep ($0.66%{\pm}0.02%$) milk. The non-protein-nitrogen contents varied from 0.33% to 0.62% among different milk species. The highest r-values were recorded for correlations between crude protein and casein in buffalo (r = 0.82), cow (r = 0.88), sheep (r = 0.86) and goat milk (r = 0.98). The caseins and whey proteins were also positively correlated with true proteins in all milk species. A favorable balance of branched-chain amino acids; leucine, isoleucine, and valine were found both in casein and whey proteins. Leucine content was highest in cow ($108{\pm}2.3mg/g$), camel ($96{\pm}2.2mg/g$) and buffalo ($90{\pm}2.4mg/g$) milk caseins. Maximum concentrations of isoleucine, phenylalanine, and histidine were noticed in goat milk caseins. Glutamic acid and proline were dominant among non-essential amino acids. Conclusively, current exploration is important for milk processors to design nutritious and consistent quality end products.