Stability of Tetracycline Antibiotics in Raw Milk under Laboratory Storage Conditions

1999 ◽  
Vol 62 (5) ◽  
pp. 547-548 ◽  
Author(s):  
LYNDA V. PODHORNIAK ◽  
SHANITA LEAKE ◽  
FRANK J. SCHENCK
Keyword(s):  
Metal Chelate ◽  
Raw Milk ◽  
Storage Conditions ◽  
Screening Tests ◽  
Rapid Screening ◽  
Tetracycline Antibiotics ◽  
Milk Samples ◽  
Bulk Milk ◽  
Tetracycline Residues ◽  
Metal Chelate Affinity Chromatography

Raw milk samples collected from bulk milk tankers may be screened for the presence of tetracycline antibiotics using rapid screening tests. If tetracycline residues are detected, the milk may be shipped to a laboratory for high-pressure liquid chromatography (HPLC) analysis. Because the milk may be shipped on ice blocks, it is important to know whether tetracycline residues are stable at that temperature and for how long. Control raw milk samples fortified with 50 ppb each chlortetracycline, demeclocycline, methacycline hydrochloride, minocycline, oxytetracycline, and tetracycline were incubated at 4°C or 25°C, then analyzed using a metal chelate affinity chromatography extraction and HPLC. No loss of tetracycline was observed after 48 h of storage at 4°C or 24 h at 25°C. Losses ranging from 4 to 13% and 0 to 18% were noted after 72 h at 4°C and 48 h at 25°C, respectively.

Simultaneous Determination of Multiple Tetracycline Residues in Milk Using Metal Chelate Affinity Chromatography

1993 ◽  
Vol 76 (2) ◽  
pp. 329-334 ◽  
Author(s):  
Mary C Carson
Keyword(s):  
Metal Chelate ◽  
Raw Milk ◽  
Good Precision ◽  
Milk Samples ◽  
Fortified Milk ◽  
On Line ◽  
Fast Flow ◽  
Tetracycline Residues ◽  
Metal Chelate Affinity Chromatography

Abstract A method was developed for the determination of 7 tetracyclines in milk. Raw milk samples are defatted, acidified, and centrifuged to remove proteins, and the tetracyclines are specifically absorbed from the milk by chelation with metal ions bound to small Chelating Sepharose Fast Flow columns. The tetracyclines are removed from these columns with EDTA-containing buffer, and the extracts are further cleaned up by centrifugal ultrafiltration. Finally, the extracts are concentrated and analyzed simultaneously by on-line concentration. This method has limits of detection for individual tetracyclines of <5 ng/mL and was validated with fortified milk samples at 15,30, and 60 ng/mL. Recoveries exceeded 60% for all tetracyclines at all levels, with good precision. The method was also tested on milk from cows dosed with each of the tetracyclines. Advantages of this method over existing methods include its sensitivity, minimal use of organic solvents, and speed; with an autosampler, at least 14 samples can be processed and analyzed in 1 day.

scholarly journals Assessment of ceftiofur residues in cow milk using commercial screening test kits

2019 ◽  
Vol 6 (1) ◽  
pp. e000329 ◽  
Author(s):  
Luc Durel ◽  
Guglielmo Gallina ◽  
Terence Pellet
Keyword(s):  
Screening Test ◽  
Generation Cephalosporin ◽  
Operating Conditions ◽  
Cow Milk ◽  
Screening Tests ◽  
Rapid Screening ◽  
Beta Lactam ◽  
Withdrawal Time ◽  
Milk Samples ◽  
Bulk Milk

Ceftiofur, a third-generation cephalosporin, is one of the most used antibiotics in dairy industry. Intramuscular injection of 1 mg/kgBW ceftiofur hydrochloride (HCl) generally results in 0 hour withdrawal time for the milk in dairy cows. Nevertheless, farmers and dairy processors occasionally complain about ceftiofur-based products in case of positive result to a commercial rapid screening test for the presence of violative residues of antimicrobials (inhibitors) in the bulk milk tank. Six lactating cows were injected with a 50 mg/ml ceftiofur HCl-based product at the dosage regimen of 1 mg/kg, intramuscularly, once a day, for five consecutive days, as per label. Milk samples were then collected just before the very last injection (T0) and then at 12, 24, 36, 48, 60, 72, 84 and 96 hours after the last injection. Individual milk samples were tested using three commercial screening test kits for inhibitor residues: DelvotestSP NT, SNAP Beta-Lactam ST Plus and ROSA MRL Beta-Lactam Test. Since bulk tank is screened in real operating conditions, samples were also diluted to 1:4, 1:10 and tested again. For the Delvotest SP NT, which lowest detected concentration is close the MRL of the ceftiofur (100 µg/kg), all results were negative. For the ROSA MRL Beta-Lactam Test and the SNAP Beta-Lactam ST Plus, several samples yielded positive and doubtful results at T0 and T12. However, after dilution to 1:10, all results were negative. Consequently, when used as officially instructed, the tested 50 mg/ml ceftiofur HCl-based injectable veterinary products are safe, and milk should be free of violative residues of ceftiofur. With consideration to the low specificity and the low positive predictive value of commercial screening tests, positive reactions of the bulk milk should be interpreted as false positive or another risky usage of β-lactam-based medicines in the farm must be investigated.

scholarly journals Simultaneous Determination of Multiple Tetracycline Residues in Milk by Metal Chelate Affinity Chromatography: Collaborative Study

1996 ◽  
Vol 79 (1) ◽  
pp. 29-42 ◽  
Author(s):  
Mary C Carson ◽  
Wayne Breslyn ◽  
J Carmany ◽  
S Cross ◽  
W H Farrington ◽  
...  
Keyword(s):  
Metal Chelate ◽  
Collaborative Study ◽  
Raw Milk ◽  
Milk Samples ◽  
Relative Standard ◽  
Control Milk ◽  
Fast Flow ◽  
Tetracycline Residues ◽  
Liquid Chromatographic

Abstract To meet federal and state regulatory needs, a liquid chromatographic (LC) method with ultraviolet (UV) detection was developed for determination of 7 tetracyclines at 30 ng/mL in milk. Raw milk samples are defatted, acidified, and centrifuged to remove proteins, and tetracyclines are specifically absorbed from the milk by chelation with metal ions bound to small Chelating Sepharose Fast Flow columns. Tetracyclines are removed from these columns with EDTA-containing buffer, and extracts are further cleaned by ultrafiltration. Finally, extracts are concentrated and analyzed simultane ously by using on-line concentration. This method was validated in a collaborative study that involved 11 laboratories, including the authors’ laboratory. Each laboratory was asked to prepare and analyze known control and fortified milk samples, as well as 18 coded blind samples. Eight laboratories completed all analyses. Average interlaboratory recoveries for the known fortified samples ranged from 59% (methacycline at 15 ng/mL) to 78% (oxytetracy cline at 60 ng/mL). Average recovery for each of 7 residues at 30 ng/mL were between 60 and 110%, meeting single-residue guidelines for accuracy set by the U.S. Food and Drug Administration. Reproducibility relative standard deviation (RSDR) for the known fortified samples varied from 11 to 39%, with 6 of 7 residues at the 30 ng/mL level having RSDR values at or below 20%. Seven of 8 laboratories correctly identified blind control milk samples and all 28 residues present in blind samples. The metal chelate affinity—LC method for determination of multiple tetracycline residues in milk has been adopted first action by AOAC INTERNATIONAL.

Preservation and Storage Mechanisms for Raw Milk Samples for Use in Milk-Recording Schemes

1996 ◽  
Vol 59 (2) ◽  
pp. 151-154 ◽  
Author(s):  
HUMBERTO G. MONARDES ◽  
ROBERT K. MOORE ◽  
BRIAN CORRIGAN ◽  
YVON RIOUX
Keyword(s):  
Cell Count ◽  
Somatic Cell Count ◽  
Potassium Dichromate ◽  
Dairy Herd ◽  
Raw Milk ◽  
Storage Conditions ◽  
Sample Storage ◽  
Milk Samples ◽  
Whole Process ◽  
And Storage

This study, carried out by the Quebec Dairy Herd Analysis Service, compares (during summer conditions in Quebec) the performance of three types of preservatives for raw milk under four different systems of sample storage: no refrigeration, refrigeration at the laboratory only, refrigeration during transport and at the lab, and complete refrigeration from sampling at the farm to analysis. The objective was to determine the best preservative and storage conditions for protecting milk components during transportation and storage of raw milk samples collected at the farm and sent to a central testing lab for analysis. Milk samples were analyzed at day 3 and at day 7 after sampling to observe the effect of aging. A total of 12,480 samples were collected during the trial. The components studied were percentage of fat and protein and somatic cell count (SCC). In general, samples preserved with bronopol (2-bromo-2-nitropropane-1,3-diol and 2-bromo-2-nitropropanol) in liquid or in microtab tended to give higher readings for fat and protein contents than samples preserved with potassium dichromate. Significantly lower fat values were observed in 7-day-old samples compared to 3-day-old samples. Fat depression was more accentuated in nonrefrigerated samples. Under current methods of handling raw milk samples, refrigeration during the whole process of sampling, transportation, and until analysis, seems an ideal to attain to avoid significant reductions of fat values.

scholarly journals Determination of Fat, Protein, and Lactose in Raw Milk by Fourier Transform Infrared Spectroscopy and by Analysis with a Conventional Filter-Based Milk Analyzer

1996 ◽  
Vol 79 (3) ◽  
pp. 711-717 ◽  
Author(s):  
Dominique Lefier ◽  
Remy Grappin ◽  
Sylvie Pochet
Keyword(s):  
Fourier Transform ◽  
Fourier Transform Infrared ◽  
Raw Milk ◽  
Milk Composition ◽  
Milk Samples ◽  
Bulk Milk ◽  
Different Seasons ◽  
Standard Deviations ◽  
True Protein ◽  
Single Calibration

Abstract The accuracy of fat, crude protein (CP), true protein (TP), and lactose determinations of raw milk by Fourier transform infrared (FTIR) spectroscopy and by analysis with a conventional filter-based milk analyzer was assessed in 6 trials performed over a 10-month period. At each trial, 30 bulk milk samples collected from 15 European countries and 11 reconstituted milks made from raw milk components were analyzed. When calibrations were performed with reconstituted milks at each trial, accuracy standard deviations for fat, CP, TP, and lactose were, respectively, 0.050,0.048,0.035, and 0.076 g/100 g for the filter instrument and 0.047, 0.046,0.042, and 0.065 g/100 g for the FTIR instrument. When a single calibration was made instead of calibrations at each trial, accuracy standard deviations increased for the filter instrument to 0.130, 0.119,0.121, and 0.083 for fat, CP, TP, and lactose, respectively, and for the FTIR instrument to 0.082, 0.053,0.044, and 0.084 g/100 g. Because the FTIR instrument provides more spectral information related to milk composition than does the filter instrument, single-calibration FTIR analysis of milk samples collected in different seasons is more accurate. Using reconstituted milks, prepared such that there is no correlation between fat, CP, and lactose, provides a more robust calibration than using genuine bulk milk, especially when milks with unusual composition are analyzed.

COMPARISONS OF MASTITIS SCREENING TEST RESULTS FROM QUARTER, BUCKET AND BULK MILK SAMPLES1,2

1967 ◽  
Vol 30 (1) ◽  
pp. 7-12 ◽  
Author(s):  
D. S. Postle
Keyword(s):  
Test Scores ◽  
Screening Test ◽  
Dairy Farms ◽  
Screening Tests ◽  
Test Results ◽  
Milk Samples ◽  
Bulk Milk ◽  
Leukocyte Counts ◽  
Bulk Tank ◽  
One Year

Summary Milk from four dairy farms in southern Wisconsin was examined over a period of one year in a study that was undertaken: (a) to determine the agreement between results of mastitis screening tests when applied to bulk, bucket and quarter milk samples; (b) to determine the relative efficiencies of five mastitis screening tests using direct microscopic leukocyte counts as a standard, and (c) to examine the quality, as determined by leukocyte content and screening test results, of the milk from all quarters contributing to the bulk tank on each farm. Most screening tests examined, when applied to quarter milk samples, gave a higher correlation with direct microscopic leukocyte counts than when applied to either bucket or bulk milk samples. Similarly, efficiency ratings of screening tests applied to quarter samples were higher than those for the same tests applied to bulk samples. Three of the four farms examined maintained bulk tank milk screening test scores that failed to suggest the presence of milk from a substantial number of quarters that were shedding abnormal numbers of leukocytes.

scholarly journals The effect of cattle breed, season and type of diet on nitrogen fractions and amino acid profile of raw milk

2013 ◽  
Vol 56 (1) ◽  
pp. 709-718 ◽  
Author(s):  
L. Křížová ◽  
O. Hanuš ◽  
P. Roubal ◽  
J. Kučera ◽  
S. Hadrová
Keyword(s):  
Amino Acid ◽  
Milk Yield ◽  
Cattle Breed ◽  
Raw Milk ◽  
Amino Acid Profile ◽  
The Other ◽  
Nitrogen Fractions ◽  
Milk Samples ◽  
Bulk Milk

Abstract. The aim of the study was to describe the differences in nitrogen fractions and deepen the knowledge in the amino acid profile of raw milk affected by the breed of cattle, season and type of feeding. The study was conducted from June 2005 to February 2007 on 64 bulk milk samples collected from eight herds consisting of Czech Fleckvieh (four herds) and Holstein (four herds) breed. One half of the herds of each breed was grazed while the other half was not. Samples were collected twice in winter and twice in summer. The effect of the breed resulted in differences in milk yield that was lower in Czech Fleckvieh (5 385.50 kg) than in Holstein (7 015.15 kg, P<0.05). The content of nitrogen fractions was higher in Czech Fleckvieh than in Holstein (P<0.05). No effect of the breed on the amino acid profile of milk was observed except on the concentration of Glu (P<0.05). The effect of the season was demonstrated in the decrease of the concentrations of nitrogen fractions and Met during summer in comparison to winter (P<0.05). The effect of the type of feeding resulted in lower milk yield (5 197.50 and 7 203.75 kg) and lower concentrations of nitrogen fractions in grazed herds compared to non-grazed herds (P<0.05), respectively. Furthermore, the amino acid profile of milk differed significantly between grazed and non-grazed herds (P<0.05).

A COMPARISON OF SCREENING TESTS TO DETECT ABNORMAL MILK1

1969 ◽  
Vol 32 (9) ◽  
pp. 365-368 ◽  
Author(s):  
G. Nageswararao ◽  
H. E. Calbert
Keyword(s):  
Optical Density ◽  
Catalase Activity ◽  
Screening Tests ◽  
Milk Samples ◽  
California Mastitis Test ◽  
Fresh Milk ◽  
Bulk Milk ◽  
Microscopic Count ◽  
Insignificant Correlation

The results of the Feulgen-DNA-color optical density and score, the California mastitis test (CMT) score, viscosity developed in milk samples by addition of equal volume of CMT reagent, the catalase test, the (direct microscopic count bf leucocytes, and the proportion of live leucocytes were compared using fresh, quarter, and bucket milk samples and 1 to 2 day old bulk milk samples. The Feulgen-DNA-color gave. good correlations with all the tests in all types of samples, except with the CMT of bulk samples. The CMT score and viscosity gave good correlations with all the tests on fresh milk samples and insignificant correlation with stored milk samples. The catalase test gave good correlations with all other tests in fresh samples and low but significant correlations with stored samples. Quarter and bucket milk samples contained 71% and 74% live leucocytes and bulk milk samples contained 42% live leucocytes. Holding of milk at 5 C for 5 days did not significantly change the Feulgen-DNA-color and catalase activity, slightly increased total leucocyte counts, but gradually decreased the CMT score, the viscosity, and the proportion of live leucocytes. The Feulgcn-DNA-color of milk samples containing few millions of leucocytes and the direct microscopic count of total, leucocytes gave poor reproducibility.

Serological and bacteriological evaluation of brucellosis in milk of small ruminants

Food Research ◽  
2021 ◽  
Vol 5 (4) ◽  
pp. 216-222
Author(s):  
D.A. Almashhadany
Keyword(s):  
Public Health ◽  
Test Performance ◽  
Health Hazard ◽  
Small Ruminants ◽  
Raw Milk ◽  
Rapid Screening ◽  
Brucella Species ◽  
Milk Samples ◽  
Animal Populations ◽  
Significant Public Health

Brucellosis continues to be a serious infection to human and animal populations in developing countries with detrimental impacts on public health and food animal production. This work aimed to estimate the prevalence of brucellosis in sheep and goats’ raw milk samples at Kirkuk Governorate, Iraq by identifying anti-Brucella antibodies and isolation of Brucella species. A total of 430 raw milk samples (210 sheep milk and 220 goats’ milk) were randomly collected from dairy females during the period from July to December 2019. The results showed an overall prevalence of Brucella antibodies in 12.3% and 10.7% of animals according to MRT and indirect ELISA, respectively. The overall isolation of Brucella species from raw milk samples was 10.0%. The isolated species of Brucella were B. abortus (37.2%) and B. melitensis (62.8%). An observable increase in occurrence during autumn (September to November) was detected, while autumn progress was associated with declining in brucellosis. In conclusion, brucellosis is still a significant public health hazard in Kirkuk Governorate. Based on test performance, the study recommends MRT as a rapid screening test for detecting brucellosis in milk in farms, centres, and dairy factories. Consumers are also recommended to sufficiently pasteurize the milk in order to kill this milk-borne pathogen before consumption.

A Collaborative Study to Determine the Feasibility of Using 0.40-, 0.20-, 0.14-, and 0.10-Inch-Diameter Discs to Measure Sediment in Fluid Milk

1977 ◽  
Vol 40 (1) ◽  
pp. 41-42
Author(s):  
EARL O. WRIGHT ◽  
WARREN S. CLARK ◽  
RICHARD W. WEBBER ◽  
WILLIAM L. ARLEDGE ◽  
MICHAEL H. ROMAN ◽  
...  
Keyword(s):  
Collaborative Study ◽  
Raw Milk ◽  
Laboratory Personnel ◽  
Milk Samples ◽  
Bulk Milk ◽  
Sediment Content ◽  
Trained Personnel ◽  
Fluid Milk

This collaborative study was done to determine whether laboratory personnel could successfully grade raw milk for sediment content using 0.40-, 0.20-, 0.14-, and 0.10-inch-diameter sediment discs. The 0.40-inch disc presently is accepted for grading sediment in mixed bulk milk samples. Technicians in 17 separate laboratories made 1,360 determinations (80 per laboratory) or 20 determinations for each size of sediment disc. Each laboratory graded the same set of samples. Samples were graded using photoprint standards that were prepared for this study. The laboratories were evaluated on the ability of laboratory technicians to grade the various sizes of sediment discs. Technicians in 13 of the 17 laboratories graded samples showing no significant differences in their ability to grade the various sized sediment discs. Four laboratories were not consistent in their ability to grade discs and showed significant differences in agreements with the previously determined sediment level as the diameter of the disc was reduced. Based on these results, most laboratories evaluated were capable of grading sediment discs with diameters of 0.40-, 0.20-, and 0.14-inch with consistency. With properly trained personnel in the laboratories, the study indicates the 0.10-inch diameter disc also can be used effectively for grading sediment in milk.

Sign in / Sign up

Export Citation Format

Share Document