A liquid chromatographic-tandem mass spectrometric (LC-MS/MS) multi-residue method for simultaneous quantification and identification of 37 anthelmintic veterinary drug residues (including benzimidazoles, macrocyclic lactones, and flukicides, levamisole, pyrantel and niclosamide) in milk has been developed and validated. For sample preparation, we used a simple modification of the QuEChERS (quick, easy, cheap, effective, rugged and safe) method, which was initially developed for analysis of pesticide residues. Anthelmintic residues were extracted into acetonitrile:methanol (9:1, v/v) using sodium chloride to induce liquid-liquid partitioning followed by dispersive solid phase extraction for cleanup. The extract was concentrated into dimethyl sulphoxide, which was used as a keeper to ensure that analytes remain in solution. Using rapid polarity switching in electrospray ionization, a single injection was capable of detecting both positively and negatively charged ions within a 15 min run time. The Limit of detection (LOD) and the Limit of quantification (LOQ) method ranged from 0.1 ng/g to 4.4 ng/g and from 0.3 ng/g to 14.6 ng/g, respectively. Validation of the developed method was based on international guidelines. Average recoveries ranged from 70% to 120%, except for 54.7% at 0.5× MRL (rafoxanide) and 69.0% at 0.5× MRL (closantel). The coefficient of variation for the described method was less than 15% over the range of concentrations studied. The result of the method was verified successfully by participation in a proficiency study for analysis of anthelmintic drugs.

A confirmatory method based on liquid chromatography with tandem mass spectrometry was developed for determination of 12 aminoglycosides in milk. Extraction of aminoglycosides from milk was performed using by liquid extraction using a 10 mM phosphate buffer containing 2% (w/v) trichloroacetic acid, followed by performance of a solid-phase clean-up procedure on a hydrophilic-lipophilic balance solid-phase extraction (HLB SPE). Ion-pair chromatography, using a mixture of 20 mM heptafluorobutyric acid (HFBA) in water and acetonitrile as the mobile phase, was used for retention of aminoglycosides on a reversed-phase C18 column. Mass spectral acquisition was performed in the multiple reaction monitoring mode, selecting two precursor ion>product ion transitions for each target compound. Satisfied recoveries (70.1～109.6%) of all aminoglycosides were demonstrated in spiked milk at three levels from 50 ng/g to 200 ng/g. The coefficients of variation ranged from 3.2% to 14.0%. The limits of quantitation (LOQs) for aminoglycosides ranged from 2.5 ng/g to 40.3 ng/g.

The current standard solutions for somatic cells used for calibration of electronic somatic cell counts as reference material in raw milk are preserved with bronopol, boric acid, sodium azide, or potassium dichromate, and have a shelf-life of only up to 6 days at 4 ± 2℃. In the present study, a set of somatic cell standard solutions (SCSS) with a stability of 5 months for calibration of electronic instruments was developed. Somatic cells collected from cow’s milk and stored in a bulk tank at a dairy plant were treated with 10% formaldehyde in order to improve stability, and then separated by centrifugation. The resulting somatic cell suspension was preserved with glycerin, thimerosal, and dimethyl sulfoxide, and diluted in 3% processed skim milk solution ranging from 200,000～250,000 (low level), 350,000～ 450,000 (medium level), and 550,000～650,000 (high level) cells/㎖. Each SCSS was verified by direct microscope somatic cell counting (DMSCC), C-reader, and commercial standard samples. The average somatic cell count determined by DMSCC was 248, 214, 226 × 103 cells/㎖, 436, 382, 420 × 103 cells/㎖, and 612, 595, 609 × 103 cells/㎖. The coefficient of variation representing the repeatability of DMSCC decreased as the number of cells increased, and was <10.0% in almost all SCSS samples (range 4.6～7.1%). No statistically significant difference in somatic cell concentration was observed after storage at refrigeration temperature (2～6℃) over a period of 22 weeks (5 months). The stabilized SCSS may be useful as a reference material for determination of somatic cell count and quality control in testing of bovine raw milk.

본 연구에서는 밀크 카제인과 WPU를 이용한 하이브리드 수지를 합성하였다. 합성한 하이브리드 수지를 피혁(Full-Grain) 표면에 코팅을 하여 카제인이 하이브리드수지에 어떤 영향을 주는지에 대해 분석 하였다. 내용제성 테스트 데이터에 의하면 WPU 와 하이브리드 수지 양쪽 모두 높은 물성치를 나타내었다. 인장 강도 측정치에서는 WPU 단독 결과(2.130 kgf/mm2)가 가장 낮은 수치를 나타내었으며, WPC-3(WPU 91: casein resin 9)의 경우가 가장 높은 인장력(2.191 kgf/mm2)을 나타내었다. 또한 내마모도 측정에서는 WPC-3(50.090 mg.loss)가 좋은 물성값을 나타내었다. 연실률의 경우 WPU(637 %) 단독 코팅물의 분석값이 가장 높은 637%로 알 수 있었다.

Antibiotic resistance in animal isolates of enterococci is a public health concern, because of the risk of transmission of antibiotic-resistant strains or resistance genes to humans through the food chain. This study investigated phenotypic and genotypic resistances profile of tetracycline in 245 Enterococcus isolates from bovine milk. A total of 245 enterococci were isolated from 950 milk samples. The predominant strain was E. faecalis (n = 199, 81.2%) and E. faecium (n = 25, 10.2%). E. avium (n = 7, 2.9%), E. durans (n = 6, 2.5%), E. gallinarum (n = 4, 1.6%), and E. raffinosus (n = 4, 1.6%) were also isolated. Of the 245 enterococcal isolates 76.3% (n = 187) displayed tetracycline resistance (≥ 16 μg/ml). Of the 187 tetracycline-resistant isolates, 83.4% (n = 156), 16.1% (n = 30), and 26.7% (n = 50) possessed the genes tet(M), tet(L), tet(S) respectively. While 3.2% (n = 6) of the tetracycline- resistant isolates possessed all three genes tet(M) + tet(L) + tet(S), 8.6% (n = 16), 16.0% (n = 30), and 2.7% (n = 5) of them possessed two genes tet(M) + tet(L), tet(M) + tet(S), and tet(L) + tet(S) respectively. The tetracycline resistance pattern investigated in this study was attributable mainly to the presence of tet(M).

농산물의 안전성 확보와 품질평가를 위해서 신속하고 경제적인 비파괴 검사법에 대한 연구 및 기술개발이 활발하게 이루어지고 있다. 그러나 분광된 빛을 이용하여 내부 품질평가 과정에서 발생할 수 있는 분석 대상체의 성분 변화에 미치는 영향에 대한 연구는 미비한 실정이다. 따라서 본 연구는 분광분석을 이용하여 원유의 성분분석 과정에서 분광된 빛이 원유의 성분 및 체세포에 미치는 영향을 구명하고자 수행되었다. 본 연구에 사용된 원유는 일본 시가현 소재 낙농가에서 채취된 것으로 유지방, 유단백질, 유당, 무지고형분, 총고형분, 유요소, 구연산 및 체세포수를 화학적 방법에 의해 측정하였다. 또한 인위적으로 분광된 빛은 5가지 영역대로 구분하여 원유에 각각 1분, 5분, 10분간 주사하였다. 연구결과, 400 nm이하 파장대인 자외선 영역에서 유지방이 2.6% 증가되는 경향이 있었고, 체세포수도 9.0% 증가된 것으로 분석되었다. 그러나 다른 원유 성분에는 변화가 없는 것으로 나타났다. 따라서 자외선 영역의 빛을 원유 품질 평가에 적용하기 위해서는 보다 다양한 원유 시료에 대한 추가 검증이 필요할 것으로 사료된다.

Our objective in this study is to assess the safety of docosahexaenoic acid (DHA) fortified milk of dairy cows fed feeds containing protected fish oil treated with formaldehyde by analyzing formaldehyde concentration in commercial milk and DHA fortified milk of dairy cows fed formaldehyde treated feed. There are 3 milk samples in this study: Commercial milk (CM), DHA fortified milk for Kid (DHA-K) and DHA fortified milk for Baby (DHA-B). We confirm the fresh quality of these three samples by physicochemical tests. In fat content result, three groups are significantly different at the p < 0.05 by Duncan's multiple range test, but fat content of group DHA-K is about half the level of the other two groups. Protein content of group DHA-K is 1% higher than other two groups. According to the analysis result of DHA content of DHA fortified milk, DHA content of DHA-B is two-fold higher than DHA-K. Similar pattern was seen in the intake based on age. According to HPLC analysis result of formaldehyde concentration in milk, commercial milk and DHA fortified milk are between 0.013 ppm and 0.057 ppm which is formaldehyde standard level in fresh milk settled in WHO (World Health Organization). Three groups have no significantly differences at the p < 0.05 by Duncan’s multiple range test. For this reason, it can be concluded that there is no transition of formaldehyde from dairy cows fed formaldehyde treated feeds to its produced milk. Safety about formaldehyde of DHA fortified milk of dairy cows fed formaldehyde treated feeds is considered similar to commercial milk.

본 시험은 포도부산물의 첨가가 젖소의 산유량, 유성분 및 혈액 성상에 미치는 영향을 조사하기 위하여 실시하였다. 비유중기 젖소 8두(평균 월령: 89.8, 평균 유기: 164.4, 평균 산차: 2.8산)를 공시하였으며, 포도부산물을 첨가하지 않은 대조구와 1일 1 kg을 첨가한 시험구로 두 처리구를 설정하여 3주간 급여하였다. 유지방, 유단백, 유당 및 총 고형물 함량은 처리간에 차이가 없었다. 그러나 산유량은 포도부산물 을 첨가한 처리구가 23.13 kg/d으로 대조구의 21.16 kg/d에 비해 높은 반면(p<0.05), 체세포 수는 대조구가 포도부산물 처리구에 비해 높았다(p<0.05). 혈중 glucose, alanine aminotransferase, total protein 및 blood urea nitrogen 함량은 처리구간 차이가 없었으나, AST와 총콜레스테롤 함량은 대조구 (123.75 IU/L, 200.82 mg/dl)가 포도부산물 처리구(95.34 IU/L, 180.63 mg/dl)에 비해 높았다(p<0.05). 이상의 결과에서, 다양한 생리활성을 가진 포도부산물은 젖소를 위한 기능성 사료로 이용 가능성이 높을 것으로 사료된다.

Ovulation synchronization (ovsynch) has proved to increase the number of insemination in cattle by overcoming the problems of heat detection. The aim of this study was to do ovsynch in water buffaloes where heat detection is a major reproductive problem and to determine the conception rates after timed artificial insemination (TAI). Twenty cyclic buffaloes at 60 days postpartum were selected by examining 24 unobserved estrus buffaloes based on milk progesterone assay (progesterone concentration 1.0 ng/ml) from the Mymensingh district of Bangladesh. Ovsynch treatment regimen was started irrespective of the stage of estrous cycle. Gonadorelin (500 ) was injected intramuscularly at Day 0 followed by Alfaprostol (8 mg) at Day 7. A second injection of Gonadorelin was given at Day 9 and TAI was done with frozen semen from Mediterranean buffalo bulls at 16~20 hours of the second Gonadorelin injection. Milk progesterone ELISA at Day 10~12 post AI confirmed ovulation in 16 out of 20 (80%) buffaloes (progesterone concentration 1.0 ng/ml). High progesterone concentration ( 1.0 ng/ml) at Day 10~12 and Day 22~24 of AI showed pregnancy in six out of 20 (30%) buffaloes. Pregnancy was further confirmed by ultrasonography at Day 40 in these six buffaloes. In conclusion, ovsynch followed by TAI could be applied in cyclic buffaloes for overcoming the estrus detection problems; however, more studies are needed to increase the conception rate.

본 연구는 허브 부식토를 이용하여 첨가 수준별 in vitro 반추위 발효특성 평가와 젖소를 이용하여 급여시 유생산성에 미치는 영향을 조사하기 위하여 본 연구를 수행하였다. 시험 1에서는 티머시 건초를 기질로 하여 허브부식토(herbaceous peat)를 0,1 및 5%를 3반복으로 각각 첨가하여 in vitro 반추위내 pH, 가스발생량, VFA (volatile fatty acid), ammonia-N 및 건물분해율을 조사하여 반추위내 발효성상의

A total of 222 udder-half milk samples of lactating goats were collected from two herds in Korea during 2008 and all samples were subjected to bacteriological examination. Somatic cell counts (SCC) were also determined for all samples except for 13 (5.9%), which were collected from halves of udders with clinical mastitis. A total of 85 bacteria were isolated from 82 (36.9%) of 222 milk samples tested. Staphylococci were the predominant pathogens, accounting for almost 70% of the isolates: Coagulase negative staphylococci (CNS) and S. aureus constituted 55% (47/85) and 14.1% (12/85), respectively. Among 209 samples tested for SCC, bacteria were isolated from 36 of 115 (31.3%) samples with SCC of <1×106 cells/㎖ and 38 of 94 (40.4%) samples that had SCC of ≥1×106 cells/㎖, respectively. All S. aureus were detected from samples with SCC of ≥1×106 cells/㎖, while 25 of 47 (61.0%) CNS were isolated from milk samples with SCC of <1×106 cells/㎖. Mean SCC of milk samples that harbored S. aureus and CNS was 4,787×103 cells/㎖ and >1×106 cells/㎖, respectively. All S. aureus and CNS isolates were susceptible to all antimicrobials tested except for penicillin, to which 2 (16.6%) S. aureus and 12 (25.5%) CNS isolates showed resistance.

Three-hundred samples of powdered infant formula milk and related products from four different manufacturers in 2010 were collected and surveyed their contaminations for aerobic bacteria, coliform, Enterobacter (Cronobacter) sakazakii, and food-borne pathogens. Fifteen samples of sterilized infant formula milk were all negative on these microorganisms. In all collected products of unsterilized infant formulas and follow-on infant formulas,aerobic bacteria were detected at 239 (83.9%) among 285 samples, and they all were found below 10³ cfu/g. Coliform bacteria were also detected at four among 285 samples. Salmonella spp. and Ent. sakazakii, weren't detected at the all samples. Bacillus cereus was detected at 24 (8.4%) among 285 samples. The level of B. cereus was below 100 cfu/g but it was suitable for the range of specification of B. cereus in infant formulas. Clostridium perfringens, Escherichia coli O157:H7, Staphylococcus aureus and Listeria monocytogenes weren't also detected. In consequence, it was suitable for total viable count, coliform and potential pathogen to the specification of infant formulas and related products.

This study was carried out to elucidate changes in milk production, milk components and milk product properties as influenced by organic and conventional farming system. Milk production in transient organic feeding was lower by 7.6% than that in conventional feeding and also milk fat, milk protein content, solids not fat and somatic cell count were lower than conventional farming system. But, milk lactose content in transient organic feeding was higher than that in conventional feeding. Ca and Fe content in milk in organic feeding tended to be higher compared to conventional feeding. Linoleic acid and unsaturated fatty acids in milk in organic feeding was higher than those in conventional feeding and properties of milk products were improved in organic milk compared to conventional milk.

본 시험은 섬유질배합사료(TMR)의 에너지 및 단백질 수준이 다를 경우, 비유초기 유산양의 사료섭취량 및 유생산에 미치는 영향을 조사하기 위하여 수행하였다. 시험 동물은 자넨종 생후 16개월령 전후의 초산 착유양 24두를 시험구별 6마리씩 공시하였으며, TMR의 에너지와 단백질 수준은 대조구(Control)가 TDN 67.0%, CP 13.9% (NRC, 2007), 에너지 증량구(T1)는 TDN 73.7%, CP 13.9%, 단백질 증량구(T2)는 T

A simple, selective and sensitive procedure for the confirmation of 14 sulfonamide antibacterials in milk was developed. The milk samples were homogenized, extracted and deproteinized by acetonitrile and defatted by n-hexane. Analysis was performed by liquid chromatography with tandem mass spectrometry (LC-MS/MS) in positive mode for all 14 analytes. Mass spectral acquisition was performed in the multi reaction monitoring mode (MRM), selecting two structurally significant transitions per compound. The calibrations were performed in sample matrixes and the interference effect of sample matrixes on the ionization was effectively eliminated. Good linear relationship (R2=0.992～ 0.999) were observed at 6 concentrations of 2.5～100 ng/g. Satisfied recoveries (86.3～110.2%) of all sulfonamides were demonstrated in spiked milk at three levels from 5 to 20 ng/g. The limits of quantitation (LOQs) for sulfonamides ranged from 0.25～2.1 ng/g.

본 시험은 산양유 생산을 위해 유기사료를 이용하여 유산양의 적정 에너지 및 단백질 공급 수준과 조농비율을 결정하기 위하여 비유중기 Saanen종 유산양 4두( BW)를 이용하여 라틴방각법으로 실시하였다. 대사에너지 공급수준과 단백질 공급수준을 10.59 (T1), 10.14 (T2), 9.45 (T3) 및 8.75 (T4) MJ/kg과 11.90 (T1), 12.73 (T2), 15.19 (T3) 및 16.60% (T4)로 달리하였으며, 조농비율은 49

본 시험은 산양유 생산을 위해 유가사료를 이용하여 유산양의 적정 에너지 및 단백질 공급 수준과 조농비율을 결정하기 위하여 비유중기 Saanen종 유산양 4두(57.5土10.8 kg BW)를 이용하여 4x4 라틴방각법으로 실시하였다. 대사에너지 공급수준과 단백질 공급수준을 10.59 (T1), 10.14 (T2), 9.45 (T3) 및 8.75 (T4) MJ/kg과 11.90 (T1), 12.73 (T2), 15.19 (T3) 및 16.60% (T4)로 달리하였으며, 조농비율은 49:51 (T1), 59:41 (T2), 74:26 (T3) 및 90:10 (T4)의 네 처리구로 나누었다. 사료 섭취량 및 체중은 모든 처리구 사이의 유의한 차이가 없었다. 유량은 T3구에서 가장 높았으며, T2 및 T4구와 비교 하여 유의하게 높게 나타났다(p<0.05). 유지방 함량과 생산량은 T4구에서 다른 처리구와 비교하여 가장 낮았다(p<0.05). 유단백질과 유당 생산량은 T1 (61.29 및 70.95 g/일)과 T3 (60.52 및 75.82 g/일)구에서 T2 (50.49 및 59.64 g/일)와 T4 (52.49 빛 59.82 g/얼)구와 비교하여 유의하게 높게 나타났다. 결과적으로 유산양의 유생산성을 극대화시커기 위해서 에너지 공급수준은 최소 9 MJ/kg 이상과 단백질 공급수준은 최소 15% 이상을 공급해 주어야할 것으로 기대된다.