Streptomycin Residues In Milk Research Articles

Use of ELISA technique for detection of streptomycin residues in milk

This study involved examination of 45 milk samples were distributed as: 15 imported milk powder, 10 imported liquid milk, 10 local cow's milk, 10 local sheep's milk. These samples were collected from September 2010 to April 2011 at different markets in Mosul city (Iraq) in order to detect level of streptomycin residue using Enzyme Linked ImmunoSorbent Assay (ELISA) technique. The results showed that the percentage of positive samples of streptomycin residue in milk was 53.3%, and as follow 15.6% in the local sheep's milk samples, 13.3% in the local cow's milk samples, 11.1% in the imported liquid milk samples and 13.3% in the imported milk powder samples with mean value of 22.8, 20.1, 12.6 and 19.9 µg/kg milk, respectively. From these results, it is clear that all samples of milk had residual streptomycin level within the permissible limits and it is regarded as safe for human consumption.

Highly sensitive chromatographic time-resolved fluoroimmunoassay for rapid onsite detection of streptomycin in milk

Antibiotic residues are major contaminants in milk because of their use in agriculture and animal husbandry. In particular, streptomycin, an aminoglycoside antibiotic, is a potential risk to consumers because of its ototoxicity, anaphylaxis, and growth inhibition. Herein, monoclonal antibodies for streptomycin were conjugated with europium microspheres to serve as detection probes for the development of a chromatographic time-resolved fluoroimmunoassay to detect streptomycin residues in milk. The method had a low detection limit of 0.58 µg/kg, a linear range of 0.8 to 6.25 μg/kg, and substantial recovery, from 85.6 to 108.3%. It showed slight cross-reactivity with another aminoglycoside analog. Strong correlations between the results of established chromatographic time-resolved fluoroimmunoassay and ultra-performance liquid chromatography-tandem mass spectrometry indicated that the established fluoroimmunoassay is a reliable method for rapid onsite detection of streptomycin in milk and it has great potential in food safety monitoring.

METHODS FOR SANITARY SURVEILLANCE OF LIVESTOCK PRODUCTION. VII. ENZYMOIMMUNOASSAY OF STREPTOMYCIN

Summary The polyclonal rabbit antibodies against streptomycin conjugated with bovine serum albumin in reaction with diglycidyl ether of 1,4-butanediol presents high specificity to streptomycin and its similar structural analog — dihydrostreptomycin. In the con- ditions of indirect competitive enzymoimmunoassay with immobilized antigens, heterologous to immunogene on protein carrier and methods of synthesis, the limit of streptomycin detection is 0.1 ng/ml. The authors consider the use of developed immunoenzyme test- systems for control of antibiotic contamination in milk and eggs with the limit of detection of 10 mkg/kg and in meat with the limit of 20 mkg/kg. Streptomycin (SM) is aminoglycoside antibiotic widely used for many years in our country and abroad for the treatment of acute infectious diseases of animals, despite its dangerous side effects such as allergic reactions, disorders of neuromuscular conduction, and ototoxicity (1 2). In modern practice, the control of SM residues in animal products is often based on enzyme-linked immunosorbent assay (ELISA). This method was implemented in several countries in the form of test systems of various types including biosensor technology (3-12). Russian researchers also have proposed a test system based on direct ELISA and the evaluation test using immunochromatography for the control of SM in milk and dairy products (13, 14). The purpose of this work was obtaining specific immunoreagents based on streptomycin, optimization of conditions of the indirect competitive solid-phase immunoassay, and assessing the applicability of this test system for the control of SM residues in milk, eggs and meat. Technique. The experiment was performed using the following chemicals: streptomycin sulfate, diglycidyl ether of 1,4- butanediol, adipic acid dihydrazide, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDCI), human transferrin (HT) (Sigma, USA ), sodium borohydride (Serva, Germany), dihydro-streptomycin (G.F. Gauze Research Institute of New Antibiotics, Moscow), dimethylformamide (Fluka, Germany), bovine serum albumin (BSA), gelatin (Gel) and antispecies enzyme conjugate prepared according to the description (15) from horseradish peroxidase (EC 1.11.1.7) and donkey antiserum to rabbit immunoglobulin, sodium periodate of domestic production. ELISA was conducted on high-binding polystyrene plates (Costar, USA) using a photometer Dynatech MR 5000 (Dynatech, Germany). The reaction with diglycidyl ether of 1,4-butanediol for the synthesis of conjugates of SM with BSA and Gel - BSA- SM(100)e, Gel-SM(10)e, Gel-SM(30)e, and Gel-SM(100)e: 6,8 mg SM sulfate (10 umol) in 1 ml 1% NaHCO3 was added with 14 ul (10 umol) diglycidyl ether of 1,4-butanediol (10% solution in dimethylformamide) and stirred at room temperature for 24 hours. Then, 4 mg BSA (0,06 umol) in 0,5 ml of 0,05 M carbonate-bicarbonate buffer (CBB, pH 9,5) was added with 600 ul of the abovementioned mixture (100-fold molar excess of hapten), and three portions of 4 mg Gel (0,025 umol) in 0,5 ml CBB - with, respectively, 25; 75, and 250 ul (10-, 30-, and 100-fold molar excesses), then stirred for 3 hours and dialyzed . The reaction with adipic acid dihydrazide for the synthesis of SM conjugates with BSA and Gel- BSA-SM(100)h, Gel- SM(10)h, Gel-SM(30)h, and Gel-SM(100)h: firstly, 4 mg BSA (0,06 umol) and 12 mg Gel (0,075 umol) (resp., in 0,5 and 1,5 ml water) were added with EDCI (resp., 15 and 30 mg), stirred for 30 minutes, and then the mixture with Gel was divided to 3 equal portions. Then, an aqueous solution of 6,8 mg SM sulfate (10 umol) was added with 1,8 mg of adipic acid dihydrazide and stirred at room temperature overnight. After that, the portion with BSA was added with 600 ul of the mixture containing the reaction product of SM and adipic acid dihydrazide (100-fold molar excess), while the portions with Gel - with, respectively, 25; 75, and 250 ul (10-, 30-, and 100-fold molar excesses), then stirred for 2 hours at room temperature and dialyzed.

Monoclonal antibody-based ELISA and colloidal gold-based immunochromatographic assay for streptomycin residue detection in milk and swine urine

A protein conjugate of streptomycin (streptomycin-bovine serum albumin (BSA) conjugate) was prepared and used as immunogen to produce monoclonal antibodies (MAb). One hybridoma secreting anti-streptomycin MAb was obtained and then used to produce MAb. The MAb named 13H5 showed the 50% maximal inhibitory concentration (IC(50)) value of 4.65 ng/ml and the IC(20) value of 0.21 ng/ml in phosphate buffered saline (PBS). At optimum conditions, an indirect competitive enzyme-linked immunosorbent assay (ELISA) and a colloidal gold-based immunochromatographic assay (CGIA) were developed and applied to detect streptomycin residues in milk and swine urine samples. The developed ELISA showed that the minimum detection limit was 2.0 and 1.9 ng/ml for milk and swine urine samples, respectively, without obvious cross-reactivity to other tested antibiotics except dihydrostreptomycin which gave a 118.32% cross reaction value. Milk and swine urine samples spiked with streptomycin at 10, 50, 100 and 200 ng/ml were analyzed by the established ELISA. The mean recovery of streptomycin was from 81.9% to 105.5% and from 84.3% to 92.2% for milk and swine urine, respectively. The optimized CGIA showed that the minimum detection limit was 20.0 ng/ml for milk and swine urine samples. The results of spiked analysis and specific analysis demonstrate that the CGIA could be applicable for screening milk and swine urine samples for the presence of streptomycin residues on-site. The established ELISA and CGIA allow the rapid, low-cost, and sensitive determination of streptomycin residues in food samples.

Flow‐injection determination of streptomycin residues in milk using the luminol–periodate–Mn2+ chemiluminescence system

A novel flow-injection method with chemiluminescence detection was developed for the determination of streptomycin residues in milk, based on the enhancement by streptomycin of the luminol-potassium periodate-Mn(2+) chemiluminescence system. The assay allowed analysis of streptomycin residues in whole milk samples ( approximately 3.5% fat) after sample work-up procedures. The limit of detection was 5.16 x 10(-9) mol/L for milk, and was far below the regulations of maximum residue limits (MRLs). The relative standard deviation (RSD) for 8.66 x 10(-8) mol/L streptomycin was 1.94% (n = 15) in milk. The results obtained for the assay of streptomycin residues in milk was comparable with those obtained by the official methods (ELISA) and demonstrated good accuracy and precision. The possible mechanism is briefly discussed.

Diffusion test for the detection of streptomycin residues in milk.

Diffusion test for the detection of streptomycin residues in milk.

An Improved Microbiological Procedure for Detection of Streptomycin Residues in Milk and Animal Tissues

A method is described which allows detection of 0.025 µg streptomycin sulfate per ml. This represents an improvement of sensitivity by 8 times when compared with the currently used method. By adding penicillin to the assay medium in subinhibitory concentrations, a synergistic effect of streptomycin and penicillin is exerted towards the test organism, Bacillus subtilis, resulting in an increased sensitivity to streptomycin.