• Journal of Nutrition and Health
• /
• v.28 no.2
• /
• pp.144-151
• /
• 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 Service
• /
• v.20 no.1
• /
• pp.79-93
• /
• 1997

The sulfonamide is one of potentiative antimicrobial agents which is being used widely in veterinary medicine for control of several animal diseases such as mastitis as well as for promotion of growth. However, the misusages of sulfonamides in food producing animals, especially cattle produce several considerable problems in human health caused from residues of this antibiotic in milk product. To determine the most effective analytical methods for residual sulfonamides in raw milk, this study was performed comparatively using by some applicable screening detecting method such as TTC, Charm II test (sulfonamides), and Lactek tests (sulfamethazine kit). The positive result from screening tests was confirmed by HPLC method. Milk samples (540 raw milks) were collected from dairy farms. Results of this study are summariezed as follorrs ; 1. All samples (540 raw milks) showed negative response from TTC test, however, 18 raw milks of those samples responded positively to Charm II test. 2. By Lactek test, residual sulfamethazine was detected from 4 raw milks. Fifteen raw milks of 18 samples which were classified as positive one by Charm II test, showed positive response 3. Retention time of sulfonamides added at the level of 100ppb into sklm milk was ranged from 1.55 minute to 23.3 minute. Recovery rates of sulfonamides were variable from 6.7% upto 94.2% depended on the types of sulfonamlde. 4. Single type of sulfonamides was detected from 10 raw milk samples, 2 types of sulfonamides from 3 samples and 3 types from 2 raw milks by HPLC. 5. Sulfonamides was detected in this study were 5 types : 11 samples for sulfisomidine, 5 samples for sulfamethazine, 3 samples for sulfadlmethoxine, 2 samples for sulfathiazole and 1 sample for sulfadiazine. 6. The highest levels of residual sulfonamides was 210.3 ppb of sulfamethazine but the lowest concentration of residue was 2.2 ppb of sulfamethazine and sulfisomidine, respectively. Number of samples detected positively in this experiment were belows : above 100 ppb for 1 sample (4.5%) (sulfamethazine), 50~100 ppb for 4 samples (18.1%) (each 2 samples for sulfamethazine and sulfisomidine, respectively), 25~50 ppb for 6 samples (27.1%) (2 sulfisomidine, each 1 sample for sulfadiazine, sulfadimethoxine, sulfamethazine and sulfathiazole, respectively), 10~25ppb for 3 samples (13.7%) (3 sulfisomidine), and below 10ppb for 8 samples (36.4%) (4 sulfisomidine, 2 sulfadimethoxine and each 1 for sulfamethazine and sulfathiazole).

• Korean Journal of Veterinary Service
• /
• v.15 no.2
• /
• pp.101-108
• /
• 1992

This study was carried out to investigate the effect of sulfamethazine and trimethoprim on TTC test in raw milk. Ten raw milks which does not contain any antibiotics were collected from milk farms and one hundred twenty raw milks which collected from three raw milk receiving stations and those milk samples were mixed up sulfamethazine and trimethoprim for TTC test. The results were as follows ; 1. Positive reactions of TTC test were shown above the concentration of 3, 000ppm for sulfamethazine and 10ppm for trimethoprim. 2. When the TTC test was conducted with trimethoprim and sulfamethazine mixture, a pair of the concentration of trimethoprim and sulfamethazine shown to positive reaction were 0.1-2, 000ppm, 0.5-1, 000ppm, 1.0-250ppm and 2.0-100ppm, respectively. 3. Of 120 raw milk samples tested, 16 samples(13%) were shown quasi-positive reaction when the trimethoprim at the concetration of 2ppm was added in the samples.

• Korean Journal of Food Science and Technology
• /
• v.24 no.4
• /
• pp.393-395
• /
• 1992

The ${\alpha}-lactalbumin({\alpha}-la)$ concentration in raw and laboratory-heated milks by HPLC was 1.20 mg/ml (unheated), 1.17 mg/ml ($63^{\circ}C$, 30min), 1.13 mg/ml ($72^{\circ}C$, 15sec) and 0 mg/ml ($100^{\circ}C$, 10min), respectively. Whereas, ${\alpha}-lactalbumin$ concentration ranges of commercial milks were $1.00{\sim}1.02\;mg/ml$ (pasteurized), $0.23{\sim}0.68\;mg/ml$ (UHT-pasteurized) and $0.77{\sim}0.89\;mg/ml$ (UHT-sterilized), respectively. It was supposed that the ${\alpha}-lactalbumin$ content of sterilized milk will be lower than that of UHT milk, but the opposite occurred. This discrepancy would be caused by the different heating system in the milk plants, where indirect UHT-treatment had more heat intensity than direct UHT-processing. The HPLC determination of ${\alpha}-lactalbumin$ may be an indicator to evaluate correctly and rapidly heated milks.

• Korean Journal of Food Science and Technology
• /
• v.44 no.2
• /
• pp.247-250
• /
• 2012

Raw milk samples (n=28) obtained from milk tanks in 3 dairy plants of different regions and commercial milks (n=100) were collected from six cities. These samples were analyzed for the level of aflatoxin $M_1$ contamination using immunoaffinity columns and high performance liquid chromatography coupled with fluorescent detectors. Confirmation of aflatoxin $M_1$ ($AFM_1$) identified in positive samples was based on the formation of the hemiacetal derivative ($AFM_{2a}$) after derivatization with trifluroacetic acid. The average concentrations of aflatoxin $M_1$ in the raw milks were 25.1 ng/kg, and those values in commercial milks were 29.8 ng/kg. The highest level of aflatoxin $M_1$ in milk was 72.7 ng/kg. These results showed that the contamination of aflatoxin $M_1$ in milks consumed in the Korea was quite low compared to the standard in Korea Food Code (aflatoxin $M_1$ 500 ng/kg).

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.20 no.6
• /
• pp.546-550
• /
• 1991

Changes of pH, titratible acidity, undenatured whey protein contents and the rates of loss of available lysine in market milks were investigated to find out the effective indicators for identification and classification of different heat treatment. There showed no change of both pH and titratiable acidity among the heating methods in market milks. The contents of undenatured wheyprotein per 100ml serum were determined as 413.7mg(LTLT), 341.3mg(HTSP), 6.9mg(UHT pasteurized) and 96.6mg(UHT sterilized), respectively. Distinct differences of underatured whey protein contents accoriding to the heating method could be observed. The rates of loss of available lysine in heated milks compared to raw milk showed 1.4% (LTLT), 0.2%(HTST), 6.3%(UHT pasteurized) and 4.9%(UHT sterillized), respectively. The rates of loss of available lysine were not suitable to classify the UHT heating method.

• Journal of the korean veterinary medical association
• /
• v.20 no.2
• /
• pp.103-108
• /
• 1984

A total of 359 cultures of Staphylococcus were isolated from no raw milk samples in stock farms of Gyeongnam province from December, 1981 to May, 1982. Some biochemical properties and antimicrobial drug susceptibility of the isolaes were studied with the

• Food Science of Animal Resources
• /
• v.35 no.4
• /
• pp.459-465
• /
• 2015

Bovine milk provides essential nutrients, including immunologically important molecules, as the primary source of nutrition to newborns. Recent studies showed that RNAs from bovine milk contain immune-related microRNAs (miRNA) that regulate various immune systems. To evaluate the biological and immunological activity of miRNAs from milk products, isolation methods need to be established. Six methods for extracting total RNAs from bovine colostrums were adopted to evaluate the isolating efficiency and expression of miRNAs. Total RNA from milk was presented in formulation of small RNAs, rather than ribosomal RNAs. Column-combined phenol isolating methods showed high recovery of total RNAs, especially the commercial columns for biofluid samples, which demonstrated outstanding efficiency for recovering miRNAs. We also evaluated the quantity of five immune-related miRNAs (miR-93, miR-106a, miR-155, miR-181a, miR-451) in milk processed by temperature treatments including low temperature for long time (LTLT, 63℃ for 30 min)-, high temperature for short time (HTST, 75℃ for 15 s)-, and ultra heat treatment (UHT, 120-130℃ for 0.5-4 s). All targeted miRNAs had significantly reduced levels in processed milks compared to colostrum and raw mature milk. Interestingly, the amount of immune-related miRNAs from HTST milk was more resistant than those of LTLT and UHT milks. Our present study examined defined methods of RNA isolation and quantification of immune-specific miRNAs from small volumes of milk for use in further analysis.

• Korean Journal of Veterinary Service
• /
• v.38 no.1
• /
• pp.25-30
• /
• 2015

Bee venom has been used as to prevent and treat bovine mastitis as natural antimicrobial compounds in some dairy cattle farms in Korea. It is needed to determine the residual of bee venom in milks of dairy cattle treated with bee venom. Since bee venom is not approved as a raw material for animal drugs, the preprocessing method to detect bee venom residual in milk and the tolerance limit for its residue has not been established yet in Korea. Therefore, the purpose of this study was to develop pre-processing method not affecting major component of bee venom for detection of its residue in milks using ultra-high performance liauid chromatography (UHPLC). In addition, bee venom residue was also analyzed in milk samples of dairy cattle treated for mastitis with bee venom using UHPLC with the developed pre-processing method in this study. As a result, melittin, histamin and phospolipase A2, the major components of bee venom, were all detected by UHPLC with the pre-processing method developed in this study. The results of this study suggest that the pre-processing method developed in this study can be useful to detect bee venom residue in dairy cattle milk. We also found that no bee venom residues were detected in milk samples collected from dairy cattle treated with bee venom after 1 and 3 days, respectively.

• Korean Journal of Veterinary Service
• /
• v.14 no.1
• /
• pp.63-69
• /
• 1991

Antibiotic residues of raw milks collected in Anyang area were tested by TTC-reduction test, EEC-4plate method and TLC(SOS-kit ) method to improve and monitor the quality of milk. Antibiotic substances were not detected from 100 raw milk samples, but sulfamethazine was detected from only one sample(1.3PPM) by SOS test. Unclassified anti-microbic substances were detected from 22 samples by EEC-4 plate method. EEC-4 plate test was useful to categorize the species of antibacterial substances and SOS test was useful to detect the sulfamethazine field screening test.