Residues In Meat Research Articles

Analysis of Amoxicillin and Tetracycline Residues in Chicken Meat Using High Performance Liquid Chromatography-Mass Spectrometry

Antibiotics are commonly used as food additives in broiler farms and their use tends to be excessive regardless and incorrect that can leave some antibiotic residues in chicken meat. The aimed of this study was to analyze on antibiotic residues level amoxicillin and tetracycline in chicken meat sold in Medan. The antibiotic residues analysis was conducted by extracting the antibiotic from chicken meat with water and acetonitrile (2:8, v/v) and detected by high performance liquid chromatography-mass spectrometry detector using C-18 column (4.6 mm i.d., length 30 mm, particle size 1.8 µm) at 35 oC, with the mobile phases, 0.1 % formic acid solution in water and 0.1 % formic acid solution in methanol with gradient elution technique at a flow rate of 0.5 ml/minute. The result exhibited that the chicken meat that were collected from five markets in Medan apparently contained antibiotic residues tetracycline . The level of tetracyclin residue in chicken meat was 0.1157-1.4436 µg/g, which exceed the maximum level for tetracyclin residue allowed in foodstuffs of animal origin which is 0.1 ug/g.
 
 Keywords: residue, antibiotic, amoxicillin, tetracycline, chicken meat

Advanced applications of nanotechnology in veterinary medicine.

The invention of new techniques to manipulate materials at their nanoscale had an evolutionary effect on various medical sciences. At the time, there are thousands of nanomaterials which can be divided according to their shape, origin, or their application. The nanotechnology provided new solutions for old problems. In medical sciences, they are used for diagnostic or therapeutic purposes. They can also be applied in the preparation of nanovaccines and nanoadjuvants. Their use in the treatment of cancer and in gene therapy opened the door for a new era in medicine. Recently, various applications of nanotechnology started to find their way in the veterinary sector. They increasingly invade animal therapeutics, diagnostics, production of veterinary vaccines, farm disinfectants, for animal breeding and reproduction, and even the field of animal nutrition. Their replacement of commonly used antibiotics directly reflects on the public health. By so doing, they minimize the problem of drug resistance in both human and veterinary medicine, and the problem of drug residues in milk and meat. In addition, they have a great economic impact, by minimizing the amounts of discarded milk and the number of culled calves in dairy herds. Nanotechnology was also applied to develop pet care products and hygienic articles. The present review discusses the advantage of using nanomaterials compared to their counterparts, the various classes of nanoparticles, and illustrates the applications and the role of nanotechnology in the field of veterinary medicine.

Demonstration of oxytetracycline residues in cattle meat and offal

Accurately, ninty samples of meat, liver and kidneys were collected from abattoirs from different places in Qalyobia and Gharbia governorates for detection of their oxytetracycline residues by using HPLC and various cooking methods (boiling, frying and grilling) were applied on beef and offal for detection and study the effect of heat treatment on such antibiotic residue levels. The obtained results indicated that oxytetracycline residues were detected in 23.33%, 33.33% and 40% of the examined samples of beef, liver and kidneys, respectively and the level of OTC residues (µg/kg) in the examined samples of meat, liver and kidneys ranged from 26.8 to 346.5 with mean value of 151.79 ± 11.64, from 58.1 to 1921.4 with mean value of 822.56 ± 37.36 and from 72.3 to 3118.9 with mean value of 1457 ± 42.81, respectively. Accurately, 90%, 80% and 76.67% of examined samples of beef, liver and kidneys, respectively were accepted. This accordance to MRL of OTC (200µg/kg for meat , 600 µg/kg for liver and 1200 µg/kg for kidneys) which stipulated by US code of federal regulations (2003), FAO/WHO (2004), Egyptian Organization of Standardization and Quality Control “EOSQC” No. 3692 (2008). The effect of different cooking methods (boiling, frying and grilling) on oxytetracycline (OTC) residues in beef and offal samples revealed that before boiling, frying and grilling the concentration of OTC residues in cattle meat were 26.8 ug/kg, 195.2 ug/kg and 346.5 ug/kg. After boiling, the concentrations of OTC residues were 0 ug/kg, 12.4 ug/kg and 198.9 ug/kg and the reduction % was 100%, 93.7%and 42.6%, respectively. After frying, the concentrations of OTC residues were 0 ug/kg, 0 ug/kg and 57.1 ug/kg and the reduction % was 100%, 100% and 83.5%, respectively. After grilling, the concentration of OTC residues were 0, 0 and 26.8 ug/kg and reduction% was 100%, 100% and 92.3%, respectively.

A Flow Injection Chemiluminescent Immunosensor for Ultrasensitive Detection of Brombuterol Based on Resin Beads and Enzymatic Amplification

This study described the use of a rapid and sensitive flow injection chemiluminescence immunoassay based on the specific binding of antigens and antibodies for the detection of brombuterol residues in the swine meat and feed samples. Carboxylic resin beads were used as a solid-phase carrier for supporting more coating antigens through acylamide bonds. Under the mechanism of competitive immunity, the brombuterol in solution competed with the coating antigen immobilized on the resin beads for the limited binding sites of antibody. Then, horseradish peroxidase-labeled secondary antibodies were introduced into the immunosensor to combine with polyclonal antibodies. The chemiluminescence intensity of the luminol-p-iodophenol-H2O2 system was catalyzed by horseradish peroxidase, and thus, signal amplification was achieved. Under the optimal conditions of the concentration of coating antigen, antibody and enzymatic secondary antibody, brombuterol could be detected quantitatively. The chemiluminescence intensity decreased linearly with the logarithm of the brombuterol concentration in the range of 0.001 to 300 ng mL−1. The limit of detection (3σ) and the limit of quantitation were 0.33 pg mL−1 and 1.1 pg mL−1, respectively. This method had undergone a series of test conditions and exhibited good specificity, stability, and reproducibility. The immunosensor can also detect real samples and provide prospects for the detection of other small molecule compounds, such as isoproterenol, enrofloxacin, and ofloxacin.

Analysis of Diethylstilbestrol Residues in Chicken Using Surface-Enhanced Raman Spectroscopy (SERS) Coupled with Multivariate Analysis.

Estrogen residues, including diethylstilbestrol in chicken, are one of the main food safety concerns all over the world owing to a series of negative effects on the human body. Surface-enhanced Raman spectroscopy (SERS) coupled with multivariate analysis was applied to detect rapidly diethylstilbestrol residues in chicken. The detection conditions, including the sizes of colloidal gold nanoparticles (Au NPs) and the additional amounts of Au NPs, chicken extract containing diethylstilbestrol, and magnesium sulfate solution, as well as the adsorption time, were optimized by a single factor experiment to obtain a better detection effect of diethylstilbestrol residues in chicken. Partial least squares regression (PLSR) was the best quantitative model for the detection of diethylstilbestrol residues in chicken by comparing four chemometric models. Diethylstilbestrol residues in chicken could be predicted by PLSR with the low root mean square error (RMSE = 0.4128 mg/L), and the high determination coefficient (R2 = 0.9811) and ratio of prediction to deviation (RPD = 7.2566) for the test set. A novel approach, which has the potential for the analysis of other estrogen residues in meat, was developed to detect rapidly the diethylstilbestrol residues in chicken by using SERS coupled with multivariate analysis.

Drug residues in poultry meat: A literature review of commonly used veterinary antibacterials and anthelmintics used in poultry.

Poultry meat is widely consumed throughout the world and production practices often include the administration of pharmaceutical products. When appropriate, extra-label drug use of medications is necessary, but scientifically derived drug withdrawal intervals must be observed so that poultry meat is not contaminated with drug residues which could pose health risks to consumers. Over the past decade, there has been increased advocacy for judicious use of antimicrobial drugs for treating food animals. Judicious use of medications is commonly referred to as practices that reduce antibiotic resistance, but also includes residue avoidance. In that light, many investigators have performed scientific studies and have published estimated pharmacokinetic parameters for veterinary medications used in commercial avian species. This manuscript is a review of medication classes that have been studied in poultry (mostly chickens) with an emphasis on drug residue depletion in poultry meat.

An Indirect Competitive Enzyme-linked Immunosorbent Assay for Simultaneous Determination of Florfenicol and Thiamphenicol in Animal Meat and Urine

Abstract A high-affinity polyclonal antibody was prepared by immunizing animals with haptens FFD and FFM. Under the optimal combination of coating antigen and antibody, an indirect competitive enzyme-linked immunosorbent assay (icELISA) for simultaneous detection of florfenicol and thiamphenicol residues in animal meat and urine samples was developed. The icELISA showed an IC50 value of 1.32 ng mL−1 for florfenicol and 2.13 ng mL−1 for thiamphenicol, respectively. The linear ranges were from 0.31 to 5.61 ng mL−1 with a limit of detection of 0.12 ng mL−1 for florfenicol, and 0.41 to 11.2 ng mL−1 with a limit of detection of 0.15 ng mL−1 for thiamphenicol, respectively. The average recoveries of florfenicol and thiamphenicol in spiked samples ranged from 77.2% to 116.0% with a relative standard deviation of less than 15%. Therefore, this proposed icELISA provided a valid detection method for florfenicol and thiamphenicol residues in animal tissue and urine samples.

Distinct Effects of Bovicin HC5 and Virginiamycin on in vitro Ruminal Fermentation and Microbial Community Composition

Antibiotics are used as feed additives for cattle to alter rumen fermentation and increase weight gain. However, this practice can potentially lead to the presence of antibiotic residues in milk and meat and the selection of multiresistant bacteria. Bacteriocins have been suggested as an alternative to antibiotics used in animal production. This work aimed to evaluate the in vitro effects of bovicin HC5 and virginiamycin on ruminal fermentation and on microbial community composition. Ruminal fluid was collected from fistulated cows fed corn silage and incubated with Trypticase (15 g L-1). Cultures treated with bovicin HC5 or virginiamycin decreased (P < 0.05) ammonia accumulation by 47.46% and 66.17%, respectively. Bovicin HC5 and virginiamycin also decreased (P < 0.05) the concentration of organic acids and gas production, but the effects were somewhat distinct. Molecular fingerprinting of the microbial community using PCR-DGGE revealed that community structure varied between treatments and were distinct from the controls. These results demonstrate that bovicin HC5 and virginiamycin have distinct effects on ruminal fermentation and modify differently the microbial community composition. These results also expand the knowledge about the effects of antibiotics and bacteriocins on bacterial and archaeal communities involved in protein metabolism in the rumen.

The Modified New Two Plates Test for Detecting Tetracycline, Beta-Lactam, and Sulfonamide Antibiotic Residues in Kidney and Muscle of Cattle Slaughtered in North-East Benin

In Benin, veterinary antibiotics are widely used for cattle breeding. This livestock contributes to 57% of the locally produced meat. The aim of this study was to assess the impact of the large use of antibiotics by determining the contamination level with antibiotic residues in bovine meat, in North Benin. Kidney and muscle samples taken from 50 bovine carcasses in the 2 main slaughterhouses of Parakou were analyzed for the presence of antibiotic residues by a screening method modified from the “New Two Plates Test” (NTPT), to identify tetracyclines, sulfonamides, and beta-lactam groups of antibiotics. Thirteen kidney and muscle samples were subjected to liquid chromatography coupled to tandem mass spectrometry analysis for the confirmation of tetracycline and sulfonamide residues. After modified NTPT screening, tetracycline residues were identified in 54% of cattle carcasses while beta-lactam and sulfonamide residues were present, respectively, in 2 and 6% of sampled animals. The LC-MS/MS analysis confirmed the presence in the kidney tissue of oxytetracycline, epi-oxytetracycline, tetracycline, and epi-tetracycline at maximum levels, respectively, of 1380, 350, 190, and 230 μg kg−1. Sulfamethazine residues were confirmed in one of cattle carcass at very high levels of 3900 μg kg−1 in kidney and 2220 μg kg−1 in muscle. Antibiotic residue levels were found above the maximum residue limit applied in the European legislation in 38% of the carcasses subjected to the LC-MS/MS analysis. These high levels of contamination with antibiotic residues are a potential threat for the health of consumers, and are of concern regarding the selection of antibiotic-resistant bacteria in animals and humans.

Antimicrobial residue occurrence and its public health risk of beef meat in Debre Tabor and Bahir Dar, Northwest Ethiopia

Background and Aim:Antimicrobial residues are the parent compounds, their metabolites, and associated impurities of veterinary drugs in any edible portion of an animal product. It can result in severe consequences in human if it is consumed concentration level higher than the standard residue limits. This study aimed to determine the prevalence and its public health risk of antimicrobial residue in fresh beef meat at Bahir Dar and Debre Tabor towns, Northwest Ethiopia.Materials and Methods:A cross-sectional study was conducted from June to November 2017. The data were collected through interview questionnaire survey and laboratory experiment using Premi®(R-Biopharm, Germany) test Kit. Data were entered; analyzed using SPSS version 20.0.Results:The result of this study showed that almost all beef farms 42 (97.67%) were using tetracycline (oxytetracycline). In addition to β-lactams, (pinstripe) 21 (48.84%), and sulfonamides drugs including sulfadimidine and diminazene aceturate each 4 (9.30%). No one beef farm has respected drug withdrawal period and lack of awareness about antimicrobial side effects in 37 (86.05%) farms. Of 250 beef cattle slaughtered, antimicrobial residue positivity were 191 (76.4%) giving a 95% confidence interval of 71.10-81.70%. Origin of beef farm system was not significantly associated (p>0.05) with antimicrobial residue positivity.Conclusion:Prevalence of antimicrobial residue in beef meat in Bahir Dar and Debre Tabor towns were high and also the drug residue detected was higher than the standard level. It implies that; it has the public health hazard.

Contamination of wild boars’ (Sus scrofa) muscles with tetracycline antibiotic from oral-delivered rabies vaccine baits

ABSTRACTTetracycline (TC) is used as a biomarker for rabies vaccine bait intended for foxes. However, there is a high probability of intake of the vaccine by other species living in the forest ecosystem, including wild boars (Sus scrofa), and TC residues can occur in the animals’ tissues. In this study, muscle samples from 144 animals were tested for the presence of TC, collected after rabies vaccine distribution. For the quantitative analysis of TC and its 4-epi form, a liquid chromatography–tandem mass spectrometry (LC-MS/MS) method was developed. The results of this study show that TC was found in 53 samples, which represents 37% of all tested animals. The concentrations were in the range 5–286 µg/kg. The preliminary results suggest that the risk exists of contamination of muscle tissue of wild boars with TC from oral-delivery rabies vaccine baits containing the antibiotic. Control should be considered of TC residues in wild boar meat for human consumption.

Stevia (<i>Stevia rebaudiana Bertoni</i>): un aditivo natural efectivo en avicultura?

En avicultura, la restricción de usar antibióticos promotores del crecimiento tanto en el nivel nacional como internacional y la demanda de los consumidores de productos naturales, han originado la búsqueda de aditivos de origen natural. Así surgen distintos agregados dietarios, denominados en su conjunto promotores naturales del crecimiento (PNC), que comprenden prebióticos, probióticos, simbióticos, ácidos orgánicos, enzimas y fitogénicos. Dentro de estos últimos, encontramos la Stevia (Stevia rebaudiana Bertoni), endulzante en humanos, que en animales de interés productivo aumenta la eficiencia productiva de los mismos. Además, según se utilicen los tallos, las hojas o sus extractos, empleando diferentes metodologías de extracción, se obtienen variados componentes bioactivos con distintos mecanismos de acción. En general, dichos componentes presentan propiedades antioxidantes, antimicrobianas, antitumorales y antifúngicas; inclusive tienen efectos positivos sobre el sistema inmunológico. En aves, estos compuestos bioactivos mejoran la eficiencia productiva en pollos, sobre todo en las primeras semanas de vida y en adultos no dejan residuos en la carne o los huevos para mejorar la salud intestinal de las aves en las primeras semanas de vida. De este modo, la Stevia o sus compuestos bioactivos serían buenas alternativas para mejorar la salud intestinal en las primeras semanas de vida, lo que se reflejaría posteriormente en una mayor eficiencia productiva y mejor calidad de la canal en aves adultas.

Effect of Method of Administration Of 17β-Estradiol On Hormonal Residues in Chicken Meat, Livers and Kidneys

Administration of hormones to broiler chickens for performance- enhancing purposes may lead todeposit of residues in their carcasses. This could be a potential human health hazard up on exposureto these residues. Therefore this study was performed on sixty chicks (one day old) were rearedunder the same condition. At 10 day old age the chicks were divided into 4 groups (control, I/Madministrated group, oral administrated group and withdrawal group). Then hormonal residues weredetected in chick’s carcasses and their livers and kidneys using Enzyme-linked immune sorbentassay (ELISA) method. The results obtained that mean values of estradiol 14.2±0.20, 20.20±0.30and 22.29±0.70 ppb in muscle, liver and kidneys of chicken, respectively. .The public healthsignificance and recommendations for the use of hormones were discussed.

Clenbuterol residue in beef meat collected from several cities in Java Island, Indonesia

<p>Clenbuterol (CLB) (see Figure 1) is an illegally animal drug of the β-agonist group that used as a promoter of growth in various farm animals. The presence of CLB residues in livestock products can cause poisoning in humans such as tremor, tachycardia, nausea and dizziness. The purpose of this research is to develop CLB residue detection method on beef detected using high performance liquid chromatography (HPLC) and to know the presence of CLB residue on 74 samples of frozen and fresh meat from several cities in Java. Samples were extracted with acetonitrile and isopropanol, then analyzed chromatographically using RDS ODS C18 column and mixed mobile phases of 50 mM NaH2PO4 and acetonitrile (80:20, v/v) and detected by photodiode array detector at 210 nm wavelength. The recoveries test at spiked concentrations of 2, 5 and 10 ng/g were 103.45, 89.27 and 89.53% for each additional concentrations. The detection limit and the quantitation limit were 0.10 ng/g and 0.31 ng/g, respectively. Analysis of 74 samples showed that CLB residue was detected in 8 samples in a concentration range of 2.40 to 15.06 ng/g and had exceeded the CLB residue maximum limit of 0.2 ng/g. To avoid the risk of the presence of CLB residues, it is necessary to regularly monitor the residue content of livestock food to ensure food safety for consumers.</p>

Effectiveness of a low‐cost household electrolyzed water generator in reducing the populations of Escherichia coli K12 on inoculated beef, chevon, and pork surfaces

Acidic and alkaline electrolyzed water (EW) were investigated for their bactericidal effects when sprayed on the surface of beef, chevon (goat meat), and pork inoculated with Escherichia coli K12. Inoculated meat samples were subjected to different treatment times ranging from 2 to 12 min and enumerated on tryptic soy agar to determine the effective log reductions of microbial populations. Acidic EW treated beef, chevon, and pork samples resulted in the highest log reductions of approximately 1.16 (4 min), 1.22 (12 min), and 1.30 log10 CFU/mL (10 min), respectively; and alkaline EW treatments resulted in 1.61, 0.96, and 1.52 log10 CFU/mL reductions at 12 min treatment, respectively. In general, no significant difference in bacterial reduction (p > .05) among the different types of meat was observed. Experimental data were used to fit two microbial reduction models. The Weibull model best described E. coli reduction from meat surfaces. Practical applications Foodborne microorganisms are responsible for a large number of outbreaks and foodborne illnesses. Several conventional methods such as heat and chemicals have been used for many years to ensure the safety of food. Meat is the most consumed food as a source of protein. Since meat is usually marketed raw, chlorine-based washing technologies are commonly preferred for surface decontamination. However, these technologies may leave some chemical residues in meat that might alter its color, flavor, and texture. Electrolyzed oxidizing water is an alternative nonthermal technology that has been used in recent years to improve the safety of food products. This study thus focuses on determining the efficacy of acidic and alkaline electrolyzed water in inactivating Escherichia coli on beef, chevon, and pork surfaces.

Assessment of Oxytetracycline Residue in Cooked and Raw Meat of Chicken Broilers Before and After the End of Official Withdrawal Period

The aim of this study was to determine and to compare the presence of oxytetracycline (OTC) residues in raw and cooked (boiled) meat before and after withdrawal period with the Maximum Residue Limits (MRL) using biological and physicochemical techniques. In animal building of 2000 broiler chickens (Gallus domesticus, breed ISA F15) and under the same conditions, 12 healthy adult chickens were selected and divided in two groups (n = 6 in each group). The sample was treated by Oxytetracycline® 20% (0.4 g/kg) during 3 days. Juices and muscles tissues were sampled twice for this assay: first, the broiler chickens were slaughtered (n = 6) 24 h after the third day of treatment. However, the second sampling (n = 6) was performed 24 h after the end of the withdrawal period. For each portions of sample, the juice meat and muscle tissues samples were collected after cooking at 80 °C during 45 min and after freezing/defrosting for the raw meat. Biological methods consisted of using four plates test (FPT) to pre-screening and Premi®Test to screening. Finally, to confirm and to quantify the accurate level of OTC in positive samples, ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS) measurements were conducted. The FPT test showed that all samples were positive. While the Premi®Test analysis showed negative results for raw meat tested and positive results for juice of meat cooked in both samples. The obtained results using UHPLC-MS/MS methods confirmed the previously results. Thus, the presence of such toxic substances in our diet constitutes a major health risk for consumers, requiring the establishment of an adequate monitoring system. There is a paucity of official withdrawal periods for veterinary medicinal products in cooking meat; a relationship between the concentrations of residues of antibiotics after waiting period and cooking is not established since meat is always cooked before consumption.

Acute and chronic toxicity assessment of benzylpenicillin G residue in heat-treated animal food products

The current level of penicillin use and its persisting residue in livestock is potentially concerning; the toxicity of penicillin residue in heat-treated animal food products (HAFP) is yet to be elucidated. In this study, the acute and chronic toxicity of benzylpenicillin G (BPG) residue in HAFP was investigated in a mouse model. The calculated LD50 of BPG heated to cooking temperature (BPHCT) was 933.04 mg kg−1 [b.w.] intraperitoneally corresponding to 3.75 times lower than its prototype. Mice fed on the experimental diet containing heat-treated beef with high BPG levels for 6 months displayed a reduction in body weight and altered serum values indicating for liver and renal function. Further, the organ ratios of intestinal and spleen were increased. Histopathological changes were observed in the liver, lung and parenchyma testis tissue. BPHCT residue induced sperm aberration and micronucleated polychromatic erythrocytes formation. Present results indicate that prolonged exposure of BPHCT at higher residue levels might have an impact on public health. Importantly the toxic concentrations of BPHCT are relatively high compared with levels that would result from the degradation of antibiotic residues in meat from animals that have received a therapeutic dose of BPG.

High occurrence rates of enrofloxacin and ciprofloxacin residues in retail poultry meat revealed by an ultra-sensitive mass-spectrometric method, and antimicrobial resistance to fluoroquinolones in Campylobacter spp

ABSTRACTAn ultra-sensitive mass spectrometric confirmation and quantification method for the determination of selected fluoroquinolones—enrofloxacin and its main metabolite ciprofloxacin—was developed and validated in poultry meat samples. The achieved limits of quantification were 1 ng kg−1 for enrofloxacin and 10 ng kg−1 for ciprofloxacin. The analysis of 40 retail poultry samples originating from Estonia, Latvia, Lithuania, Poland and France revealed that 93% of samples contained residues of enrofloxacin in the range from 3.3 to 1126 ng kg−1. Previous studies have shown high levels of antimicrobial resistance to fluoroquinolones, particularly in Campylobacter spp. and various faecal indicators isolated from broiler meat. Consequently, the revealed widespread usage of fluoroquinolones in the poultry industry may result in the further emergence of antimicrobial resistance of Campylobacter in the food chain.

Automation and applications of the tolerance limit method in estimating meat withdrawal periods for veterinary drugs

A program was written in R to facilitate the implementation of the tolerance limit method (TLM) for establishing regulatory withdrawal times for limiting drug residues in meat, milk, and eggs. The developed computer source code can use pharmacokinetic and regulatory data to calculate the drug withdrawal period according to United States Food and Drug Administration (U.S. FDA) guidelines. The code called the “Withdrawal Time Calculator (WTC)” applied this TLM method to meat samples. The program was tested with the data provided by the U.S. FDA guidance and other published data collected from in vivo studies. Additional algorithm validation data were flunixin and sulfamethazine liver concentration data from peer-reviewed publications generated by our laboratory. This manuscript reports the withdrawal period results from testing the developed WTC code. Moreover, the source code for the WTC contains a data removal algorithm, constructed according to U.S. FDA data elimination recommendations if the user chooses. The power of the WTC is that it bypasses the use of multiple platforms typically required to perform the TLM, including standard commercial spreadsheet software (i.e., Microsoft Excel) and Statistical Analysis System (SAS) while providing speed and usability. This novel program provides a platform to calculate a withdrawal period recommendation for any drug in any class of animal for various regulatory body standards and could be very helpful in cases of extra-label drug use in food animals.

Effect of temperature (cooking and freezing) on the concentration of oxytetracycline residue in experimentally induced birds.

Aim:The objective of this study was to determine the effect of varying temperatures (different cooking methods and freezing) on the concentration of oxytetracycline (OTC) residues in tissues of broiler birds.Materials and Methods:Fifty, 5-week-old birds were purchased and acclimatized for 3 weeks while being fed antibiotic-free feed and water. Four birds were then tested for residue and in the absence; the remaining birds were injected intramuscularly with oxytetracycline at its therapeutic dose. Muscle and liver samples of the treated birds were harvested and checked for OTC residues before subjecting them to boiling, microwaving, and roasting. The three plate test was used for the residue detection.Result:OTC was detected at both pH 6.0 and pH 7.2 but not detected at pH 8.0. Roasting and boiling significantly reduced the concentration of oxytetracycline in muscle by 53.6% and 69.6%, respectively, at pH 6.0, microwaving reduced the concentration by 49.1% but was not statistically significant. The same pattern was followed at pH 7.2 with reduction of 34.3%, 53.2%, and 67.7% for microwaved, roasted, and boiled. For the liver tissues, there was a significant reduction in the concentration for both pH: 6.0 (57.75%, 79.75%, and 89%; pH 7.2 (48.06%, 79.6%, and 88.79%) for boiled, microwaved, and roasted samples. Boiling had a greater reduction effect for muscle samples while roasting had a greater reduction in liver samples at both pHs. Freezing at −10°C had no effect on the concentration of OTC even after 9 days.Conclusion:The significant reduction of OTC concentration by cooking indicates that consumers may not be at risk of the effects of OTC residues in meat, but microwaving meat may not reduce the concentration below the maximum residue limit if the initial concentration is very high. Therefore, routine monitoring of drug residues in farms and abattoirs is still advocated.