• Food Science of Animal Resources
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• v.30 no.6
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• pp.997-1006
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• 2010

The objective of this study was to investigate the proximate composition, pH, meat color, water holding capacity (WHC), cooking loss (CL), cholesterol content, and trans-fatty acid content of Hanwoo beef according to quality grade and cut. Five cuts [Cheggt (strip loin), Dngsim (loin), Moksim (chuck roll), Udoon (top round), Yanggi (brisket)] were obtained from 15 Hanwoo animals [3 bulls and 12 steers, 24-30 months old]. Three animals were selected from each quality grade of $1^{++}$, $1^+$, 1, 2, and 3. The protein and moisture contents (%) were significantly higher, and the fat contents (%) were significantly lower in 3 quality grade compared to the other grades (p<0.05). pH values of chuck roll and strip loin were significantly lower in $1^+$ quality grade (5.61 and 5.51) than those in 3 quality grade (5.88 and 5.92) (p<0.05). CIE L* values were significantly higher in the $1^{++}$ quality grade group (38.52-42.69%) than in 3 quality grade (33.02-36.08) (p<0.05). In the $1^{++}$ and 2 quality grade groups, CIE $L^*$ values of loin were significantly higher than those of other cuts (p<0.05). CIE $a^*$ values of loin (28.11) in 1 quality grade were the highest, whereas those of strip loin (15.36) in 3 quality grade were the lowest (p<0.05). WHC was not significantly different among the five cuts or quality grades. In CL, loin and strip loin were significantly lower in $1^{++}$ quality grade than in 3 quality grade (p<0.05), and they were also significantly lower (22.21-24.81%) than the other cuts in the same quality grade (p<0.05). The loin in $1^{++}$ (41.26 mg/100 g), $1^+$ (43.23), and 1 quality grades (48.63) had higher cholesterol contents (%) than in 2 (36.02) and 3 quality grades (29.84) (p<0.05). Cholesterol contents of the five cuts in $1^{++}$ quality grade (39.44-43.31%) were significantly higher than those in 3 quality grade (28.09-32.39%). The trans-fatty acid contents of the five cuts were 1.08-2.72%. The loin, strip loin, brisket, and top round in 3 quality grade had significantly higher trans-fatty acid contents than those of the other grades (p<0.05).

• Korean Journal of Agricultural Science
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• v.43 no.5
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• pp.810-817
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• 2016

The aim of this experiment was to determine the effect of a high-energy diet on the level of serum metabolites and on carcass characteristics of Hanwoo steers. High energy diets have been used for enhancing intramuscular adipose tissue in high quality beef cattle. However, there is not much information about the physiological reactions to this diet. We hypothesized that a high energy diet would increase blood metabolites and the meat quality of Hanwoo steers during the early and final fattening periods. A $2{\times}2$ factorial arrangement (High, Control, and Early, Final) in a completely randomized design was used to feed 24 Hanwoo steers. Two steers were kept in the same pen and 12 pens were used for the experiment. Blood was drawn from each steer on the first week of every other month from 11 to 28 months. Overall Average Daily Gain (ADG) and feed efficiency were not different between high energy and control diets (p > 0.05). However, Dry Matter Intake (DMI greater with the control diet than DMI with the high energy diet during the final fattening period (p < 0.05). Serum non-esterified fatty acid (NEFA) concentrations were greater in the control diet group than in the high energy diet group during the final fattening period (p < 0.05). However, serum albumin, glucose, total protein, triglyceride, and phosphorus were greater in the high energy group than those of the control group (p < 0.05). Carcass traits or physico-chemical characteristics were not different between high energy diet treatment and the control. These data indicated that a high energy diet (+ 3% TDN) increased serum triglyceride during early fattening periods and decreased non-esterified fatty acids during final fattening periods in Hanwoo steers.

• Korean Journal of Food Science and Technology
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• v.43 no.1
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• pp.1-5
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• 2011

It is possible that veterinary medicines remain in livestock food products, according to the use of many and various veterinary medicines to protect against disease when livestock animals are breed in limited space. Concentrated and continuous monitoring of residues is needed due to increases in resistance to antibiotics and side effects by eating livestock food products. We developed an analysis method for detecting streptomycin, dihydrostreptomycin, neomycin, gentamicin and spectinomycin in meat using LC/MS/MS and measured sensitivity, precision, accuracy, linearity and recovery according to CODEX guidelines to acquire confidence in the analysis method. Based on the results, we acquired good sensitivity compared to the maximum residue limit (MRL) as limits of detection (LOD) were 0.002-0.016 mg/kg and limits of quantification (LOQ) were 0.006-0.050 mg/kg. The analysis method satisfied the CODEX guidelines. The linearity ($r^2$) values of aminoglycoside antibiotics were 0.9936-0.9980, recoveries were 60-110% and relative standard deviations (RSD) were within 15%. As a result of monitoring for residues in a total 250 samples of livestock foods such as pork, chicken, and beef by the confirmed method, dihydrostreptomycin and gentamicin were detected in 5 pork samples. The residues of these antibiotics were within the MRLs. Thus, the detection ratio was 2% as 5 samples were identified from 250 samples.

• Journal of Food Hygiene and Safety
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• v.5 no.3
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• pp.139-158
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• 1990

Heavy resposibility is placed on the veterinarian and the livestock and aquatic animal producers to observe the period for withdrawal of a drug prior to marketing to assure that illegal concentrations of drug residues in meat, milk, egg, fish and other animal foods do not occur. This is essential from a public health standpoint because levels of residues in excess of those legalIy permitted in edible tissues may produce injurious effects when consumed over a long time span. With greater use of animal drugs of chemicals required in production of food crops, livestock and aquatic animals, the possibility of human being continuously exposed to drug and chemical residues for a life time is unequivocally evident. Korean authorities concerned Ministry of Agriculture and Fishery and Ministry of Health and Social Affairs, have recenly made their own regulations to control chemical residues in beef, pork and chicken independently. Consequently, inspection for the chemical residues also have been or will be carried out by the two authorities concerned without any cooperations. It is undoubtfulI to have a single regulation and national residue program for control residual chemicals in animal foods and that the tolerance levels should be established in milk, egg, and freshwater fish. Besides, we have no complete standard methods to analyze the residual chemicals and the methods have not been evaluated their efficiency, precise, accuracy and limit of detection. In this paper, the analytical methods and national residue programs in foreign countries are introduced and discussed and the status of animal food safety in this country is also reviewed.

• Journal of Food Hygiene and Safety
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• v.26 no.3
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• pp.209-213
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• 2011

Physicochemical, microbiological and sensory characteristics were determined during storage at 15, 25, and 35$^{\circ}C$ for six months to predict shelf-life of four fried rice retort dishes. Thiobarbituric acid (TBA) values were increased significantly and pH and acid values did not show any significant differences. Microbiological contamination levels were estimated as safe. Sensory evaluation were tested over 4 points during storage period. It maintained the commercial value during the shelf-life. TBA value as an effective quality indicator was used to estimate shelf-life with Arrhenius equation. The estimated shelf-life were 1,408 days (46 months) for beef fried rice, 1,353 days (44 months) for Ham fried rice, 1,164 (38 months) days for chicken curry fried rice and 1,182 (39 months) days for bacon tuna fried rice. In conclusion, shelf-life of all four fried rice dishes was predicted as longer than three years (36 months) at room temperature.

• Journal of Animal Science and Technology
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• v.49 no.1
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• pp.51-58
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• 2007

Twenty Hanwoo steers (average body weight=440.8±32.4kg) were used to investigate the effects of fish oil supplementation on growth performance, fatty acid composition of longissimus muscle and carcass characteristics. The experiment was done with two treatment groups; FO-0, without fish oil and FO-3, supplemented with 3% fish oil. Total gain and average daily gain (ADG) of steers were similar between two groups. Fish oil supplementation had no effects on contents of protein, ether extract and ash in longissimus muscle. Contents of isoleucine and glycine in longissimus muscle were decreased by fish oil supplementation (p<0.05), but content of cystein was increased by fish oil supplementation (p<0.05). Fish oil supplementation decreased contents of myristic acid and eicosenoic acid in longissimus muscle (p<0.05), but increased contents of oleic acid and arachidonic acid in longissimus muscle (p<0.05). Contents of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in longissimus muscle were increased by fish oil supplementation p<0.05). Carcass weight, back fat thickness, rib-eye area, yield index and yield grade were similar between two groups. Meat color was improved by fish oil supplementation (p<0.05), Ratio of quality grade ‘1 or over’ increased by fish oil supplementation. Therefore, the present study indicating that fish oil supplementation had positive effects on content of oleic acids in relation to flavor of beef, contents of EPA and DHA in relation to human health and ratio of quality grade ‘1 or over’.

• Korean Journal of Food Science and Technology
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• v.41 no.5
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• pp.490-497
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• 2009

The present study was performed to validate an analytical method for veterinary drugs, including amoxicillin, ampicillin, oxolinic acid and flumequin, in meat, fish, and their products as established in the 2007 Korea Food Code, and to monitor the respective drugs in 6 kinds of foods, namely beef, pork, flatfish, rockfish, freshwater eel and shrimp. Additionally, an HPLC-ESI-MS/MS method was developed for the qualification of these veterinary drugs. As a result of monitoring, these drugs were detected in 14 (3.6%) out of 393 samples. In particular, amoxicillin was detected in 9 flatfish samples, and oxolinic acid and flumequin were detected in 4 samples and 1 sample of freshwater eel, respectively. The detection levels of amoxicillin ranged from 0.009 to 0.078 mg/kg, in which 1 sample of flatfish contained more than the MRL (0.05 mg/kg). Flumequin detected in 1 sample of freshwater eel, was less than the MRL (0.5 mg/kg). Therefore, the majority of detected levels were less than the MRLs, with the exception of 2 samples showing amounts that were 1-2 times higher than the MRLs. The detected veterinary drugs were identified and confirmed by the HPLC-ESI-MS/MS method created in this study.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.5
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• pp.725-732
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• 2012

This study was carried out to investigate the effects of hydrated potato starch on the quality of low-fat ttoekgalbi (Korean traditional patty) packaged in modified atmosphere conditions during storage. The ttoekgalbi was prepared from 53.2% lean beef, 13.9% lean pork, 9.3% pork fat, and 23.6% other ingredients. Two low-fat ttoekgalbi treatments were prepared by substituting pork fat with hydrated potato starch; either by 50% fat replacement (50% FR) or 100% fat replacement (100% FR). Both 50% and 100% FR increased the moisture, crude protein, and decreased fat content, cooking loss, and hardness. For MAP studies, 200 g of ttoekgalbi were placed on the tray and filled with gas composed of 70% $O_2$: 30% $CO_2$ (70% $O_2$-MAP) and 30% $CO_2$: 70% $N_2$ (70% $N_2$-MAP), and were stored at $5^{\circ}C$ for 12 d. During the storage time, both 50% and 100% FR showed higher protein deterioration, while no differences were found in CIE $a^*$, CIE $L^*$, lipid oxidation, and bacterial counts in comparison to control. The ttoekgalbi with 70% $O_2$-MAP was more red, lighter in color, and showed higher TBARS values compared with 70% $N_2$-MAP. The meat with 70% $N_2$-MAP showed lower aerobic bacterial counts in control than those with 70% $O_2$-MAP. The lower anaerobic bacterial counts were observed only in 50% FR and 100% FR packed with 70% $N_2$-MAP in comparison with 70% $O_2$-MAP. In conclusion, the fat replacement with hydrated potato starch showed no negative effects on the quality of low fat ttoekgalbi during storage and 70% $N_2$-MAP was better than 70% $O_2$-MAP for low-fat ttoekgalbi packaging.

• Korean Journal of Agricultural Science
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• v.42 no.4
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• pp.361-368
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• 2015

This study was to investigate the effect of high energy diet on characteristics of Hanwoo steers distributed by estimated breeding value (EBV). The aim of this experiment was to determine the effect of high energy diet on the high and low beef group distributed by EBV for quality grades. We hypothesized that high energy diet is able to increase quality traits in high EBV groups when fed a high energy diet. A $2{\times}2$ factorial arrangement (High energy, control vs high EBV, low EBV) in a completely random design was used to feed 26 Hanwoo steers. Blood was drawn from each steers from 11 to 28 months. ADG and feed efficiency were not different between high energy and control diet (P>0.05). The level of DMI was greater at calf and early fattening diet in low EBV groups (P<0.05). Serum glucose and tryglyceride conecntrations were increased (P<0.05) by high EBV group from 22 to 28 month old. Serum NEFA concentration were plateau at 24 months at high EBV group and steady reduced by high energy diet (P<0.05). This data indicated that high energy diets increased serum glucose and triglyceride concentrations of high EBV steers at final fattening period.

• Korean Journal of Food Science and Technology
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• v.25 no.1
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• pp.57-62
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• 1993

The influence of the storage temperature at $15^{\circ}C$ on the biochemical and structural changes in the red muscles (M. sternomandibularis) of korean native cattle postmortem were studied. The results obtained were summarized as follows; 1.5 to 2 hours postmortem the pH-value had dropped to $6.7{\sim}6.8$, after 18 or 20 hours at $15^{\circ}C$ it had reached its final pH-value (5.5). The irreversible loss of extensibility, i.e. the onset of rigor mortis, arose at $15^{\circ}C$ between 9 and 10 hours postmortem at pH 6.1 to 6.0 and R-value between 1.05/1.10. The complete loss of extensibility postmortem was reached after 18 to 20 hours at pH 5.5/5.6. Muscle and sarcomere length of korean native cattle were contracted about 20% and 15%, respectively at $15^{\circ}C$. Meat of korean native cattle had the highest shear force (4.7 kg) on 1 day after slaughter. The tenderness was increased with the ripening period prolonged and was highest at the end of the 9 day ripening period.