Residues In Animal-derived Food Research Articles

Rapid Determination of Cephalexin in Animal-Derived Food by an Indirect Competitive Enzyme-Linked Immunosorbent Assay

Cephalexin (CFE) residues in animal-derived food and its deleterious effects on human health has attracted extensive attention. In this study, a specific anti-cephalexin monoclonal antibody (mAb) was used to develop an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) with a half-maximal inhibitory concentration (IC50) of 1.83 µg/L that was suitable for the determination of cephalexin in animal-derived foods. The limit of detection (LOD) and limit of quantitation (LOQ) for cephalexin were from 0.44 to 0.58 µg/kg and 0.57 to 0.67 µg/kg, respectively. The recovery was from 90.1 to 103.6% with coefficients of variation (CV) less than 10.0%. In addition, the established ELISA method and high-performance liquid chromatography – mass spectrometry (HPLC-MS/MS) were used to analyze the samples with good correlation between the results. The results show that the established ic-ELISA is suitable for the determination of cephalexin in animal-derived food.

Veterinary drug residues in animal-derived foods: occurrence, veterinary legislation and perceived risk factors in Cameroon

The presence of veterinary drug residues in animal-derived foods (ADF) remains a public health concern in low-income countries such as Cameroon. This paper provides an overview of the current status of antimicrobial (AM) residues in ADF, veterinary legislation on the use of AM and perception of risk factors with emphasis on the need for sustainable management in Cameroon from a one health perspective. Results show that a wide range of antimicrobials is used in the country with little or no attention to good veterinary practices. Residues of commonly used AM agents including those banned for use in food animal production in high-income countries were reported. The current legislation on the use of veterinary drugs is weak and does not make provision for key concepts such as Maximum Residue Limit. Veterinarians argue that the lack of disease diagnostic facilities and excessive use of AM has led to the presence of residues in ADFs. The government and relevant agencies need to enforce regulations for the use of veterinary drugs. Further, awareness creation through educational campaigns for users and consumers as well as the implementation of measures to restrict prescription and dispensation of AM agents to recognised veterinarians are necessary. More studies on AM residues in ADFs are needed to support veterinary drug surveillance policies. This paper strongly suggests collaboration between food safety experts, animal and human health professionals as well as policymakers to help implement good surveillance of antimicrobial use and to safeguard potent AM suitable for disease control for forthcoming generations.

Estimates of Dietary Exposure to Antibiotics among a Community Population in East China.

Background: Antibiotics are widely used in clinics, livestock farms and the aquaculture industry. A variety of antibiotics in foods and drinking water may lead to important and inadvertent dietary exposure However, the profile of dietary exposure to antibiotics in humans is not well-explored. East China is an economically developed area with a high usage of antibiotics and a high rate of antibiotic resistance (ABR). This study aimed to evaluate the total intake level of antibiotics in humans via foods and drinking water based on a community population in East China. Methods: A total of 600 local residents from 194 households were recruited into this study in Deqing County of Zhejiang Province since June 2019. Each subject was asked to fill a food frequency questionnaire to report their daily consumption of foods and drinking water. Tap water samples were collected from ten households and twenty-one antibiotics of five categories were selected to detect in drinking water. Data of antibiotic residues in animal-derived foods were obtained from the notification of unqualified edible agricultural products after special supervision sampling inspection in Deqing County. The human dietary exposure to antibiotics was estimated by combining the data of antibiotic contamination in foods and drinking water, and the information of dietary consumption. Results: Of twenty-one antibiotics selected, subjects were exposed to a total of sixteen antibiotics, ranging from 15.12 to 1128 μg/day via two main dietary routes (animal-derived foods and drinking water). The overall dietary exposure level varied greatly in the antibiotics detected and their sources. Compared with other antibiotics, enrofloxacin made the most contributions in terms of dietary exposure, with a median exposure level of 120.19 μg/day (IQR: 8.39–698.78 μg/day), followed by sulfamethazine (median: 32.95 μg/day, IQR: 2.77–162.55 μg/day) and oxytetracycline (median: 28.50 μg/day, IQR: 2.22–146.58 μg/day). The estimated exposure level via drinking water (at the ng/day level, median: 26.74 ng/day, IQR: 16.05–37.44 ng/day) was significantly and substantially lower than those via animal-derived foods (at the μg/day level, median: 216.38 μg/day, IQR: 87.52–323.00 μg/day). The overall dietary exposure level also showed differences in sex and age. Males and youths were more likely to be exposed to antibiotics via dietary routes than others. Conclusions: The community population investigated in East China was extensively exposed to multiple antibiotics via dietary routes. Long-term exposure to low-dose antibiotics in animal-derived foods was the primary dietary exposure route, compared with drinking water. Enrofloxacin contributed to the major body burden of dietary exposure, based on the combination of consumption of aquatic products and considerable enrofloxacin residues in them. Although the human dietary exposure level to antibiotics via drinking water and animal-derived foods ranged from ng/day to μg/L, their chronic toxicity and the accumulation and spread of ABR may be potential hazards to humans. Therefore, long-term monitoring of antibiotic contaminations in foods and drinking water, and human dietary antibiotic exposure is warranted.

Room temperature fabrication of magnetic covalent organic frameworks for analyzing sulfonamide residues in animal-derived foods.

A magnetic solid phase extraction method based on magnetic covalent organic frameworks (TpBD@Fe3 O4 ; 2,4,6-triformylphloroglucinol (Tp) and benzidine (BD)) combined with high performance liquid chromatography has been developed to detect the sulfonamides including sulfadiazine, sulfamerazine, sulfamethazine, and sulfamethoxazole in milk and meat. TpBD@Fe3 O4 were synthesized at room temperature under mild reaction conditions with a simple and rapid operation. The TpBD@Fe3 O4 exhibited higher extraction efficiency because of the π-π and electrostatic interactions between the benzene ring structure of the TpBD and the sulfonamide molecules. The extraction conditions including the dosage of adsorbents, the type and dosage of eluent, the elution time, and the pH of the sample solution were fully optimized. The detection results showed good linearity over a wide range (50-5 × 104 ng/mL) and low detection limits (3.39-5.77 ng/mL) for the sulfonamide targets. The practicability of this magnetic solidphase extraction-high-performance liquid chromatography method was further evaluated by analyzing milk and meat samples, with recoveries of the targets of 71.6-110.8% in milk and 71.9-109.7% in pork. The successful detection of sulfonamides residues has demonstrated the TpBD@Fe3 O4 excellent practical potential for analyzing pharmaceutical residues in animal-derived foods.

Determination of plant growth regulators in animal-derived foods using QuEChERS-isotope-labeled internal standards with high performance liquid chromatography-tandem mass spectrometry

建立了高效液相色谱-串联质谱法测定动物源性食品中植物生长调节剂类农药残留量的方法。选取猪肉、牛肉、鸡肉、猪肝、鸡蛋和牛奶作为样品,样品经乙腈提取,4 g无水硫酸镁(MgSO4)和1 g氯化钠(NaCl)盐析脱水后,取上清液经50 mg N-丙基乙二胺(PSA)+50 mg十八烷基硅烷(C18)粉末净化(含150 mg MgSO4)。采用Agilent ZORBAX Eclipse Plus C18柱分离待测物,电喷雾电离,正负离子切换多反应检测模式检测,以乙腈和5 mmol/L乙酸铵水溶液作为流动相进行梯度洗脱,基质匹配内标法定量。在猪肝、鸡蛋基质中,矮壮素、噻苯隆和多效唑在0.1~100 μg/L范围内线性关系良好;在猪肉、牛肉和鸡肉中3种植物生长调节剂在0.1~50 μg/L范围内线性关系良好;在牛奶基质中,噻苯隆和多效唑的线性范围为0.05~10 μg/L,矮壮素的线性范围为0.05~5 μg/L,相关系数(r2)均大于0.990。以信噪比(S/N)≥3对应的添加水平作为检出限(LOD), S/N≥10对应的添加水平作为定量限(LOQ),矮壮素、噻苯隆和多效唑在不同基质下的LOD为0.01~0.1 μg/kg, LOQ为0.5~5 μg/kg。分别添加LOQ、2倍LOQ和10倍LOQ 3个水平的目标化合物,平均回收率为70.0%~117.4%, RSD为0.8%~16.1%。该方法操作简单、灵敏度高,采用基质匹配内标法定量,能最大限度地消除基质干扰,使检测结果更加精确,可满足动物源性食品中矮壮素、噻苯隆和多效唑残留的定量检测工作。

Preparation of monoclonal antibody and development of an enzyme-linked immunosorbent assay for the detection of ceftiofur in animal-derived foods

Ceftiofur (CEF) residues in animal-derived foods are of great concern to farmers, regulatory agencies and consumers. In this study, an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) method was established to quickly monitor CEF residues in edible animal tissues using an easy sample preparation procedure. A monoclonal antibody, 4D5, against CEF has been produced at first, which had IC50 values for CEF, ceftriaxone, cefquinome, cefotaxime and desfuroylceftiofur of 0.78 μg/L, 0.73 μg/L, 13.6 μg/L, 8.99 μg/L and 8.89 μg/L, respectively. The limit of detection (LOD) and limit of quantitation (LOQ) in artificially contaminated animal-derived foods were 0.12–0.19 μg/L and 0.20–0.30 μg/L. The recovery rates were in the range of 89.7–109.0%. The CVs were less than 6.7%. A good correlation (R= 0.9994) between the ic-ELISA and UPLC-MS/MS showed the reliability of the developed ic-ELISA. The ic-ELISA produces a sensitive, accurate and low-cost tool for the screening of residues of CEF in animal-derived foods.

Antibiotic residues in cattle and sheep meat and human exposure assessment in southern Xinjiang, China.

In recent years, antibiotics have become widely used in animal breeding. The application of antibiotics in livestock may lead to the presence of antibiotic residues in animal‐derived foods, especially meat, that may pose a threat to human health. In this study, 26 common antibiotics (eight sulfonamides, nine fluoroquinolones, four tetracyclines, and five macrolides) were screened in 88 meat samples (cattle muscles and sheep muscles, kidneys, and livers) obtained from southern Xinjiang. The antibiotics were screened via the clean‐up step based on solid‐phase extraction and determined through ultraperformance liquid chromatography–tandem mass spectrometry. Moreover, their risk to human health was analyzed. Overall, 16 antibiotics were detected with a total detection rate of 95.46%. The percentage of noncompliant samples was 28.41% with an exceedance maximum residue limit of 1.14%. The illegal use rate of the antibiotic norfloxacin was 27.27%. The estimated daily exposure doses of all compounds in adults were <102.218 ng/kg bw/day even after applying the worst‐case scenario approach. This result demonstrated that the antibiotic residues in the tested samples imposed negligible harm to people's health and had an acceptable level of food safety risk. However, the high detection frequencies found in this work indicated that the risk of antibiotic residues could not be ignored given the cumulative risk of antibiotics, particularly the emergence of bacterial resistance, to the human body. The need for effective strategies and publicity for the judicious use of antibiotics to safeguard residents’ health is immediate.

Detection and determination of spectinomycin and lincomycin in poultry muscles and pork by ASE-SPE-GC–MS/MS

An innovative study on the qualitative identification and quantitative determination of spectinomycin and lincomycin residues in poultry (chicken, duck, and goose) muscles and pork using gas chromatography-tandem mass spectrometry (GC–MS/MS) was conducted. The samples were extracted and separated with accelerated solvent extraction (ASE) and then purified and enriched by solid-phase extraction (SPE). Then, the obtained residues were derivatized with 200 μL bis(trimethylsilyl) trifluoroacetamide (BSTFA) for 60 min at 75 °C, and the derivative products were injected into a GC–MS/MS system. Under the optimized conditions, the limits of detection (LODs) and limits of quantification (LOQs) of spectinomycin and lincomycin in samples were 2.5–4.6 μg/kg and 5.7–7.6 μg/kg, respectively, the targets’ recoveries were 79.7 %–94.2 %, the determination coefficients were 0.9992−0.9998, and the relative standard deviations (RSDs) were 1.2 %–3.5 %. The method revealed good linearity, and the parameters met the European Union requirements for the detection of veterinary drug residues. Poultry muscles and pork were procured from local stores for actual sample testing, confirming the feasibility and practicability of this method. Therefore, this study established an ASE-SPE-GC–MS/MS method to detect spectinomycin and lincomycin residues in animal-derived food.

Development of a pH-dependent homogeneous liquid-liquid extraction by cold-induced phase separation in acetonitrile/water mixtures for determination of quinolone residues in animal-derived foods

A simple extraction procedure coupled with liquid chromatography-Q Orbitrap high resolution mass spectrometry (LC-Q Orbitrap HRMS) for the determination of 19 quinolones in animal-derived foods (pork, fish, egg and milk) has been developed. Sample preparation is based on homogeneous liquid-liquid extraction at pH > 9 using water-miscible acetonitrile with cold-induced phase separation. The procedure allowed one-step enrichment and cleanup of all the 19 quinolones with different logP properties to lower aqueous phase, which eliminated the process of preconcentration and re-dissolution for sample solution. Furthermore, an adsorption phenomenon was observed between conventional borosilicate glass injection vials and most of quinolones. In detection analysis, a scheduled variable full scan strategy was performed to improve detection performance in Q Orbitrap HRMS. Under optimal conditions, a superior limit of quantitation (0.028–0.192 μg/kg) in animal-derived foods was achieved using this proposed method. Lastly, this method was validated and applied successfully in real samples.

Veterinary Drug Residues in Animal-Derived Foods: Sample Preparation and Analytical Methods.

Veterinary drugs are used to treat livestock and aquatic diseases and thus are introduced into animal-derived foods, endangering consumer health and safety. Antibiotic resistance is rapidly becoming a major worldwide problem, and there has been a steady increase in the number of pathogens that show multi-drug resistance. Illegal and excessive use of veterinary drugs in animals and aquaculture has serious adverse effects on humans and on all other environmental organisms. It is necessary to develop simple extraction methods and fast analytical methods to effectively detect veterinary drug residues in animal-derived foods. This review summarizes the application of various sample extraction techniques and detection and quantification methods for veterinary drug residues reported in the last decade (2010-2020). This review compares the advantages and disadvantages of various extraction techniques and detection methods and describes advanced methods, such as those that use electrochemical biosensors, piezoelectric biosensors, optical biosensors, and molecularly imprinted polymer biosensors. Finally, the future prospects and trends related to extraction methods, detection methods and advanced methods for the analysis of veterinary drug residues in animal-derived foods are summarized.

Studies on the inhibitory properties of leaf ethanolic extracts obtained from Ficus (Moraceae) species against Aeromonas spp. strains

IntroductionThe most frequently isolated bacteria in Polish aquaculture are of the Aeromonas genus; also pathogenic to human fish consumers, they cause substantial economic losses, and require antibiotic therapy to treat. Antibiotic residues in animal-derived food provoke concern. The aim of the study was to appraise the antimicrobial activity of ethanolic extracts of Ficus plant species against Aeromonas strains.Material and MethodsLeaves of 41 Ficus species were collected from two Ukrainian botanic gardens. They were crushed, washed, homogenized in ethanol and centrifuged, and the supernatants were applied in the Kirby–Bauer disc-diffusion method to assess the susceptibility to them of Aeromonas hydrophila, A. sobria, and A. salmonicia subsp. salmonicida isolates confirmed as K886, K825, and St30 strains. Analogous assessment was also made of these bacteria’s susceptibility to sulfonamides, quinolones, tetracyclines, and one amphenicol. Data were analysed statistically.ResultsThe majority of the extracts considerably inhibited bacterial growth, A. sobria being susceptible to 14 Ficus species, A. salmonicida subsp. salmonicida to 13, and A. hydrophila to 10.ConclusionTreatment with plant extracts has promise as an alternative to antibiotic therapy. Botanic gardens may offer new sources of plant-derived agents with a broad spectrum of biological and antimicrobial action. Further research will be useful to broaden knowledge of Ficus’ therapeutic potential.

Study on Complete Antigen Synthesis of Promazine Hydrochloride

To explore the method of complete antigen synthesis of promazine hydrochloride. Based on the analysis of the molecular structure and immunogenicity of promazine hydrochloride, complete antigen was synthesized by mixed anhydride method,under the condition of excess acid, the diazotization reaction of nitrite and p-aminobenzoic acid produces diazosalt, diazonium salt reacts with promazine hydrochloride; Triethylamine and isobutyl chloroformate form a mixed anhydride, promazine hydrochloride complete antigen was synthesized by amino ligation of mixed anhydride and carrier protein bovine serum albumin (BSA), complete antigen synthesis was identified by ultraviolet spectroscopy, the characteristic absorption peaks of promazine hydrochloride, bovine serum albumin and synthetic promazine hydrochloride complete antigen were analyzed. The peak wavelength of the synthesized complete antigen, promazine hydrochloride and bovine serum albumin is different, the complete antigen synthesis of promazine hydrochloride was proved successful. The results of this study provided a basis for the rapid detection of promazine hydrochloride residues in animal-derived food by immunoassay.

Selection and truncation of aptamers for ultrasensitive detection of sulfamethazine using a fluorescent biosensor based on graphene oxide.

We developed a fluorescent aptamer/graphene oxide (GO)-based biosensor to detect sulfamethazine (SMZ) residues in animal-derived foods. The SMZ-bound aptamers were identified and screened with an improved GO-SELEX technique using non-immobilizing ssDNA library. After seven rounds of selection, six SMZ aptamers were sequenced and analyzed for secondary structure, and their affinity and specificity were assessed by binding assays. The truncated aptamer (SMZ1S: 5'-CGTTAGACG-3') with a unique stem-loop structure showed the highest affinity (Kd = 24.6nM) to SMZ and was used to develop a GO-based fluorescent aptasensor. The binding mechanism between SMZ1S and SMZ was further analyzed by molecular docking. Under optimal conditions, the fluorescent aptasensor showed low detection limits (0.35ng/mL) and a wide dynamic linear range (from 2 to 100ng/mL). The aptasensor was also validated against real samples spiked with SMZ, which showed a fluorescence recovery from 93.9 to 108.8% and a coefficient of variation of < 12.7%. Taken together, these results suggest that this novel aptasensor can be used to sensitively, selectively, and accurately detect SMZ residues in foods. Schematic illustration of fluorescent aptasensor based on aptamer/graphene oxide complex detection of of SMZ.

Determination of veterinary drug residues in food of animal origin: Sample preparation methods and analytical techniques

Veterinary drugs are widely used in animal husbandry to prevent and treat animal diseases, to promote animal growth, and to improve the conversion rate of feed. However, the use of veterinary drugs in food-producing animals may leave residues of the parent compounds, and/or their metabolites in food products resulting in harmful effects to humans. To ensure food safety, sensitive and effective analytical methods have been developing rapidly. So it is necessary to make a systematic summary of detection methods of veterinary drug residues. Sample preparation methods and analytical techniques are the two main parts of analyzing veterinary drug residues which were described in detail. Sample preparation methods, such as solid-phase extraction, liquid–liquid extraction, immunoaffinity chromatography, and QuEChERS, were summarized by the specific examples. The three types of methods, microbial, immunological, and physicochemical methods, for screening or determination were described, including microbial inhibition, enzyme-linked immunosorbent assay, colloidal gold immunoassay, fluorescence polarization immunoassay, biosensor technology, application of quantum dots, capillary electrophoresis, liquid chromatography, and liquid chromatography-mass spectrometry. In addition, the advantages and shortcomings of methods were also described. The challenges and prospects were discussed for the analysis of veterinary drug residues in animal-derived foods.

Antimicrobial drug residues in animal-derived foods: Potential impact on the human intestinal microbiome.

The use of veterinary drugs in food-producing animals may result in the presence of low levels of drug residues in these edible, animal-derived foods, with potential dietary exposure to humans. Since therapeutic doses of antibiotics have been shown to affect bacterial populations in the gastrointestinal tract microbiome and can also promote the emergence of antibiotic-resistant bacteria, there is concern that animal drugs at residue level concentrations could also perturb the intestinal microbiome composition and modify the antimicrobial resistance profile of the human intestinal microbiota. This review provides updated information on the VICH GL#36(R2), on evaluating the safety of veterinary drug residues in animal-derived foods and their effects on the human intestinal microbiome; discusses critical research knowledge gaps and challenges in evaluating the impact of drug residues in animal-derived foods on the human intestinal microbiome; and analyzes integrated basic and applied research approaches, currently being conducted at FDA, on studies that specifically address key regulatory science questions. Moreover, this review aims to emphasize future research needs on scientific methodology and provides general recommendations on drug inactivation, bioavailability, and antimicrobial resistance, to improve the safety evaluation and risk assessment of antimicrobial residues and their impact on the gastrointestinal microbiota, with the goal of ensuring food safety.

An Ultrasensitive Fluorescence Immunoassay Based on Magnetic Separation and Upconversion Nanoparticles as Labels for the Detection of Chloramphenicol in Animal-Derived Foods

In this work, an ultrasensitive fluorescence immunoassay has been proposed for the detection of chloramphenicol. The proposed assay is based on using the carboxyl-functionalized NaYF4: Yb/Tm upconversion nanoparticles with maximum emission at 482 nm under excitation at 980 nm conjugated with anti-chloramphenicol (CAP) antibody as the signal probe and the magnetic polystyrene microspheres conjugated with coating antigen as the sensing probe. The coating antigens on the sensing probes compete with CAPs to bind with the antibodies on the signal probes and the immune complexes form. Via magnetic action, these complexes can be separated to measure their fluorescence intensity. The limit of detection (LOD) of this assay for CAP in PBS is 0.01 pg mL−1, and the linear range extends from 0.05 to 100 pg mL−1 with a linear equation of y = 387.64 lgx + 1153.93 (R2 = 0.9911). The recoveries of CAP in spiked animal-derived foods range from 76.85 to 105.18%. Trace CAP levels have been measured in the real sample by the proposed fluorescence immunoassay, and the results have been verified by commercial ELISA test kit and liquid chromatography-tandem mass spectrometry. The quantitation limits of this immunoassay for CAP in the muscle tissue, milk, and honey samples are 0.25 pg g−1, 0.4 pg g−1, and 0.4 pg g−1, respectively. The fluorescence immunoassay proposed in this study can be used to highly sensitively, accurately, and rapidly detect CAP residues in animal-derived foods.

Sensitive and selective electrochemical aptasensor via diazonium-coupling reaction for label-free determination of oxytetracycline in milk samples

As one kind of tetracycline antibiotics, oxytetracycline (OTC) residues in animal-derived foods can do serious harm to human health. Though aptasensors for the detection of OTC are widely reported, label-free electrochemical aptasensor with low cost, simple preparation and good applicability should be further explored to meet the current urgent needs. In this study, a label-free electrochemical aptasensor for OTC determination was designed. The detection was based on specific recognition by the aptamer covalently-bound on the sensing interface via diazonium coupling reaction, which was verified by computer simulation. Experiment results showed that the differential pulse voltammetry (DPV) current response of the constructed electrochemical aptasensor was linear with the logarithm of OTC concentration in the range of 1.0 × 10−9 g mL−1–1.0 × 10−4 g mL−1 (R2 = 0.9897) with the limit of detection of 2.29 × 10−10 g mL−1. The proposed aptasensor indicated good selectivity, reproducibility and stability, which could be attributed to the stable modification of aptamer on the sensing interface. The OTC in the milk sample was detected by the spiked recovery method, and good results were obtained, with the recovery rate being 87.0%-99.3%. The proposed label-free electrochemical aptasensor can provide methods for low-cost, accurate and rapid detection of antibiotic residues.

Aptamer‐based ellipsometric sensor for ultrasensitive determination of aminoglycoside group antibiotics from dairy products

Residual antibiotics taken along with food consumed through the food chain are the main cause of the super-bacteria and may damage organs such as liver and kidney. Therefore, monitoring residual antibiotic levels of products in the food chain is both important and a requirement. Maximum residual limits for kanamycin and neomycin are 150 ng mL-1 and 500 ng mL-1 respectively, which are challenging for most sensor platforms. In this paper, a novel method is presented for the determination of antibiotics residues in animal-derived foods. Aptamer-based kanamycin and neomycin biosensors based on the spectroscopic ellipsometer and the surface plasmon resonance-enhanced total internal reflection ellipsometer methods as transducing element were developed. Detection limits of both sensor platforms were in the 0.1-1 nmol L-1 ranges, and the detection range was between the detection limit and 1000 nmol L-1 . Both ellipsometry-based aptasensors can be used as an alternative to the existing enzyme-linked immunosorbent assay-based method in terms of assay time (10 min), detection limit (0.22 ng mL-1 for neomycin and 0.048 ng mL-1 for kanamycin), and detection range. © 2020 Society of Chemical Industry.

Multi-dimensional fluorescence spectroscopy coupled with chemometrics in rapid antibiotic detection and discrimination

Antibiotic residues in animal-derived foods pose risk to human health including chemical poisoning and antimicrobial resistance, and therefore, constant monitoring throughout the food supply chain is important. In the present study multi-dimensional fluorescence spectroscopy (3D and 2D) coupled with chemometric tools were tested for potential application to detect, discriminate and quantify penicillin G (PG), sulfadiazine (SF) and tetracycline (TC) in milk by direct measurement. Qualitative and quantitative calibration models were developed for prediction of antibiotic residues. Results demonstrated optimal discrimination of milk samples on the basis of antibiotic type and concentration with close to 100% of accuracy. Negative correlation between antibiotic concentration and fluorescence peak height was displayed (r ≥ 0.963 and p ≤ 0.002). A great potential for quantitative antibiotic determination was established with R2 > 0.9 and low standard errors of estimation indicating acceptable precision for the developed technique. Fluorescence spectroscopy demonstrated high specificity and sensitivity with detection limit below the maximum residue limit of PG, SF and TC in milk. Therefore, fluorescence spectroscopy can be used as an alternative method for rapid screening of antibiotic residues in milk at collection centers and processing plants to ensure product quality and safety.

Hapten Synthesis and the Development of an Ultrasensitive Indirect Competitive ELISA for the Determination of\xa0Diethylstilbestrol in Food Samples

An ultrasensitive indirect competitive enzyme-linked immunosorbent assay (ic ELISA) using monoclonal antibodies (mAbs) was developed for the specific detection of diethylstilbestrol (DES) residues. To establish an ELISA based on mAbs, hapten diethylstilbestrol mono-carboxypropyl-ether (DES-MCPE) was chemically synthetized and then conjugated to bovine serum albumin (BSA) for immunization in mice. This ic ELISA was further optimized for DES determination. The sensitivity of the ic ELISA was found to be 0.49 μg/kg and the limit of detection was 0.075 μg/kg. DES residues in salmon meat and pork were tested with the recovery range from 74.0 to 85.2% and the coefficient of variation (CV) was less than 10%. Parallel analysis of DES samples from salmon meat showed comparable results from the ic ELISA with high-performance liquid chromatography. The ic ELISA provides a useful screening method for the quantitative detection of DES residues in animal-derived food.