• Journal of Dairy Science and Biotechnology
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• v.37 no.1
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• pp.15-26
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• 2019

A common belief is that human milk is sterile. However, the development of culture-independent molecular methods, especially Next Generation Sequencing, has revealed that human milk harbors diverse and rich bacterial communities. Although studies aimed at characterizing the microbiota of human milk have produced different findings, Staphylococcus and Streptococcus are presumed to be normal members of the microbiota. Factors that influence variation in the microbiota are unclear; however, the postpartum time, route of delivery, maternal obesity, and health status may be influential. The origin of the microbiota is a hotly debated topic. Human milk bacteria are thought to be introduced through bacterial exposure of the mammary duct during breast feeding and/or the entero-mammary pathway from the maternal gastrointestinal tract. Although the exact mechanism related to the entero-mammary pathway is unknown, it is presumed that bacteria penetrate the intestinal epithelium and then migrate to the mammary gland, dendritic cells, and macrophages. In this review, various relevant studies are introduced.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.22 no.3
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• pp.262-269
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• 2019

Purpose: As the importance of breastfeeding has been reinforced, human milk is often stored for practical reasons. Therefore, we evaluated optimal storage and processing methods for human milk from a nutritional standpoint. Methods: Human milk samples were collected between June 2017 and February 2018. Also, data about maternal information were collected. Human milk was analyzed for macronutrients and caloric content. The samples were subdivided into groups for nutrient analysis. The control group (fresh milk) was not stored or processed. The other groups (9 groups) consisted of samples analyzed based on different storage temperatures (room temperature, refrigerated, frozen), defrosting methods (bottle warmer, room temperature thawing, microwave oven), and storage period (1 week, 1 month, 2 months) and compared with the control group. Results: There was no statistically significant difference in the nutrient content of human milk among the collected samples. A significant change in the content of macronutrients in milk samples was observed under storage condition at different temperatures for 1 week with subsequent thawing with bottle warmer compared to fresh milk. Under storage at $-20^{\circ}C$ for 1 week with subsequent thawing with different defrosting methods, a significant change in the content of macronutrients in milk samples was observed compared to fresh milk. After storage at $-20^{\circ}C$ for different periods and thawing with a bottle warmer, a significant change in macronutrient content in milk samples was observed compared to fresh milk regardless of the storage period. Conclusion: Unlike previous guidelines, changes in macronutrient content in milk samples were observed regardless of the method of storing and thawing. Apparently, it is proposed that mothers should feed fresh human milk to their babies without storing.

• Nutrition Research and Practice
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• v.9 no.4
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• pp.433-438
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• 2015

BACKGROUND/OBJECTIVES: Breast milk is the best available food for optimum growth and development of infants and the breastfeeding rate is increasing in Korea. The purpose of this study is to measure the concentrations of macronutrients and to evaluate their changes according to lactation period in breast milk from lactating Korean women. SUBJECTS/METHODS: Milk samples were obtained from 2,632 healthy lactating women (mean age; $32.0{\pm}3.3years$), where the lactating period was up to a period of 8 months, who also volunteered to participate in the Human Milk Macronutrient Analysis Research. Lactose, protein, fat and water content in the breast milk samples were analyzed with infrared spectrometry using MilkoScan FT-2. RESULTS: The mean macronutrient composition per 100 mL of mature breast milk was 7.1 g for lactose, 1.4 g for protein and 3.0 g for fat, and energy content was 61.1 kcal. The protein concentration was significantly lower in milk samples at 1-2 weeks (2.0 g/dL) to 2-3 months (1.4 g/dL) than those at 0-1 week (2.2 g/dL), but it was similar among samples from 3-4 months to 7-8 months (1.3 g/dL). Mean lipid levels varied among different lactational period groups (2.7-3.2 g/dL), but presented no significant difference. Lactose concentration in the milk samples did not differ with lactation period. Maternal body mass index was positively related to protein and lipid breast milk contents, but was negatively related to lactose content. General linear models examining the associations between maternal variables and milk macronutrient content revealed that lactation period had a major impact on protein and lipid, but not on lactose content in breast milk. CONCLUSIONS: These results warrant future studies to explore factors that may be associated with changes in macronutrient content in human milk.

• Journal of Nutrition and Health
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• v.32 no.1
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• pp.83-89
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• 1999

The present study was conducted to investigate the yields of volume, thiamin and riboflavin from the milk of twenty-five Cesarean-section women, and their ingestion in infants. We measured the consumed volume of human milk of infants by the test-weighing method, and thiamin riboflavin contents were determined by fluorescence spectroscopy during the first 7 days postpartum. Thiamin contents of the milk averaged 24.3, 24.0, 27.4 and 30.2ug/100g. Thiamin and riboflavin contents of the milk both increased during the lactation ps mod(p<0.05). The first secretion of breast milk occurred from the 4th to 5th day postpartum in Cesarean-section women. The consumed volume of human milk was 63, 81, 104 and 133g/day at 4, 5, 6 and 7 days postpartum and the consumed volume of formula milk was 58, 176, 292, 323, 308, 321 and 318g/day at 1, 2, 3, 4, 5, 6 and 7 days postpartum and the consumed volume of formula from the human and formula milk were 26.6, 91.0, 151.0, 172.5, 169.2, 175.9 and 172.9ug/day. Total daily riboflavin ingestion from the human and formula milk were 26.6, 91.0, 151.0, 172.5, 169.2, 175.9 and 172.9ug/day. Total daily riboflavin ingestion from the human and formula milk was 48.7, 166.8, 277.6, 318.2, 312.0, 327.0 and 335.7ug/day at 1, 2, 3, 4, 5, 6 and 7 postpartum. These results suggest that the milk secretion of Cesarean-section women is delayed a few days and the yield volume of milk is less than that of normal delivery women, but thiamin and riboflavin contents of the milk are not different from those of milk of normal-delivery women.

• Journal of the Korean Applied Science and Technology
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• v.1 no.1
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• pp.49-55
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• 1984

The lipid and fatty acid compositions and vitamin E content were analyzed in 48 human mature milk, 3 infant formulas (modified milk powder) and 8 market milk samples. The total lipid content in modified milk powder was similar those in human milk and market milk when total solids content of modified milk powder was corrected to that of human milk. In comparison with human milk, modified milk powder contained a lower proportion of triglycerides and higher proportions of phospholipids, free fatty acids and cholesterol esters. The ratios of phospholipids/triglycerides, total cholesterol / triglycerides and total tocopherol/total lipids in modified milk powder were significantly higher than those in human milk and market milk. The American recommendation for linoleic acid (0.7 IU/g) could be satisfied with human milk, modified milk powder and market milk. The proportions of short- and medium-chain even numbered saturates were higher and the proportions of long-chain derivatives of linoleic (${\omega}6$ series) and linolenic (${\omega}3$ series)acids were lower in modified milk powder and market milk than in human milk. It is concluded that in view of their levels in breast milk, the polyenoic derivatives of linoleic and linolenic acids must be taken into account when assessing infant foods.

• Journal of Nutrition and Health
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• v.35 no.7
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• pp.771-778
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• 2002

The purpose of this study is to investigate the contents of protein, fat, lactose and energy in the human milk and the intake of human milk and those nutrients in breast-fed infants from 16 lactating women in Seoul area during the first 5 months postpartum. Daily human milk intake was determined by test-weighing method and the milk from 16 mothers was analyzed for protein (semimicro Kjeldahl, N $\times$ 6.38), fat (milk checker), lactose (HPLC). Energy was calculated by Atwater and milk factor. The mean intake of human milk to the 5th month of lactation was 668 $\pm$ 186 $m\ell$/day. Mean protein contents of the human milk at 0.5, 12, 3, 4 and 5 months postpartum showed 1.48, 1.35, 1.17, 1.11, 1.15 and 1.10 g/100 $m\ell$ respectively. Lipid and lactose contents of the human milk during the first S months postpartum averaged 3.38 g/100 $m\ell$ and 6.79 g/100 $m\ell$. Energy contents at 0.5, 12, 3, 4 and 5 months postpartum showed 64.2, 66.1, 68.3, 60.1, 58.9 and 61.2 g/100 $m\ell$ respectively. Protein intake of infants from the human milk was 8.22 g/day which was 54.8% of Korean RDA. Lipid and lactose intake of infants were 23.0 and 45.6 g/day. Energy intake of infants was 422.3 kcal/day which was 84.4% of Korean RDA. Total energy content was almost same value regardless of Atwater or milk factor but the energy ratio was some different. Protein and solid contents decreased the course of lactation but lactose content was less changed. These results suggest that more research were required for the RDA.

• Journal of Nutrition and Health
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• v.38 no.4
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• pp.313-319
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• 2005

Adequate vitamin $B_2$, vitamin $B_6$, folate and vitamin $B_{12}$ intakes are known to be important for the growth and development in infants. The purpose of this study was to evaluate concentrations of vitamin $B_2$, vitamin $B_6$, folate and vitamin $B_{12}$ in human milk and to investigate the relationship between vitamin B levels in human milk and dietary habits and other health-related behaviors. Milk samples were obtained from 38 healthy lactating women (aged 29.0 $\pm$ 3.2 years) who are participating in the cohort study on pregnant women. Vitamin $B_2$ concentrations in human milk were positively correlated with maternal vitamin $B_2$ intakes in lactating mothers. Vitamin $B_6$, folate and vitamin $B_{12}$ concentrations in human milk were not correlated with maternal B vitamin intakes. Vitamin $B_6$ concentrations in human milk were negatively correlated with the amount of postpartum weight loss. The vitamin B concentrations in human milk were not associated with maternal age, height, weight and parity. Mothers who were exposed to indirect smoking had lower vitamin $B_2$ concentrations, and those who reported to consume health foods had higher vitamin $B_2$ concentrations in their milk. In conclusion, lactating women need to consume more vitamin B intakes for the growth and development in infants. Further researches are needed to find other diet and health-related factors which influence on B vitamin concentrations in human milk.

• Food Science of Animal Resources
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• v.31 no.6
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• pp.827-833
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• 2011

The objective of this study was to develop a fluorogenic real-time PCR-based assay for detecting and quantifying amounts of cow milk in cow/goat milk mixtures or goat milk products. In order to quantify the exact amount of cow milk in cow/goat raw milk mixtures and commercial goat milk products, it was necessary to achieve quantitative extraction of total genomic DNA from the raw milk matrix. Both mammalian-specific PCR and cow-specific PCR were performed. A cow-specific 252 bp band obtained from the raw cow milk and raw goat milk mixtures, commercial goat milk, and two goat milk powders was identified, along with the relationship between the cow milk amount and band intensity of the electrophoresis image. The detection threshold was found to be 0.1%. The expression of cow's 12S rRNA in the cow/goat milk mixtures, commercial goat milk, and two goat milk powders was identified. The expression quantity of the milk 12S rRNA increased with increasing ratios of the cow/goat milk mixtures. Using these calibrated relative expression levels as a standard curve in the cow/goat raw milk mixtures, the contents of cow milk were 1.8% in the commercial goat milk, 9.6% in goat milk powder A, and 11.6% in goat milk powder C. However, cow milk was not detected in goat milk powder B.

• Journal of Nutrition and Health
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• v.31 no.2
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• pp.213-219
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• 1998

This study was conducted to compare and evaluate the iodide specific ion electrode method (ISE) and neutron activation analysis method (NAA) for determining iodine in human milk and cow milk. The neutron irradiation and counting operations were carried out at the TRIGA Mark-III reactor facility of the Korea Atomic Energy Research Institute. The mean concentrations of iodine in human milk samples by the ISE and the NAA were 1450$\mu\textrm{g}$/L and 1350$\mu\textrm{g}$/L, respectively. The levels were not significantly different. In cow milk samples , the mean concentrations of iodine by the ISE and the NAA were 250$\mu\textrm{g}$.L and 200$\mu\textrm{g}$/L, respectively. here, the ISE reading was significantly higher than the NAA. reading. The correlations of the two methods were 0.92(p<0.001) for human milk samples and 0.65 for cow milk samples . The coefficient of variation was 8.3% in the ISE and 4.9% in the NAA. Therefore, the iodide specific ion electrode method is sample and fast method, but probably not in processed milk since free sulfhydryl groups in milk are also detected by the iodide electrode. However, these also indicate that the ISE method may be applicable to human milk and pasteurized milk if the conventional pasteurization time-temperature relationship of standards is not exceeded. On the other hand, the NAA method , which is independent of chemical forms and matrix, can be used for determining iodine in all kinds of milk and foods.

• Journal of Nutrition and Health
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• v.26 no.9
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• pp.1098-1109
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• 1993

The purpose of this study was to investigate macro-mineral contents in human milk longitudinally from 2 days to 12 weeks postpartum. Milk samples were collected from 34 healthy lactating women. Calcium, Phosphorus, magnesium, sodium and potassium were analyzed. Concentrations of the minerals except for magnesium differed significantly within the lactation period. The levels of sodium and potassium declined linearly over the first 12 weeks of lactation, but that of phosphorus increased. Statistically significant quadratic trends were observed in phosphorus and sodium concentrations. There was no significant correlation between maternal age and mineral concentrations throughout the lactations period. In addition, no significant differences were found between the primipara and the multipara for mineral concentrations in human milk. Mineral intake of lactating women did not affect the individual mineral concentrations of milk. However, the protein and fat intake of lactating women had a significant correlation with sodium and potassium concentrations. The following four pairs of minerals : potassium and calcium, potassium and phosphorus, sodium and magnesium, and calcium and phosphorus showed a positive correlation with each other in human milk.