Antimicrobial Residues In Food Research Articles

Effect of Dietary Benzoic Acid and Oregano Essential Oil as a Substitute for an Anti-Coccidial Agent on Growth Performance and Physiological and Immunological Responses in Broiler Chickens Challenged with Eimeria Species.

To overcome the antimicrobial residues in food, benzoic acid (BA) and oregano essential oil (OEO) are used in the broiler chicken industry. Independently, both exerted anticoccidial and antimicrobial actions and improved growth performance in broiler chickens. Their effect may be multiplied when they are used in combination. This present study was carried out to evaluate the efficacy of dietary BA and OEO alone or in combination as a substitute for a commercial coccidiostatic drug on growth performance and physiological and immunological responses in broiler chickens challenged with Eimeria species. A total of 252 unsexed 1-day-old broiler chicks were equally allotted to 36 pens, each pen containing seven chicks. The pens were randomly assigned to six treatments with six pens (replicates) for each treatment (n = 6)-(i) negative control, (ii) positive control, coccidia-challenged and non-treated, (iii) supplemented with salinomycin (an anti-coccidial drug) at 60 mg/kg of feed and coccidia-challenged, (iv) supplemented with BA at 500 mg/kg of feed and coccidia-challenged, (v) supplemented with OEOat 500 mg/kg of feed and coccidia-challenged (OEO), and (vi) supplemented with BA at 500 mg/kg of feed and OEO at 500 mg/kg of feed and coccidia-challenged (B&O). The liver enzymes and thyroxine and creatinine levels were not affected (p > 0.05) both in coccidia-challenged and supplemented chickens. The BA and OEO applied separately or in combination (B&O) significantly (p < 0.05) reduced gut pathogenic bacteria (Salmonella and Escherichia coli) and Eimeria spp., and concurrently enhanced (p > 0.05) the Lactobacillus population with better body weight gain, improved feed utilization, and superior hematological values. It also up-regulated (p > 0.05) the interferon-γ gene expression and down-regulated (p < 0.05) the interleukin-10 and Toll-like receptor-4 gene expression to protect the chickens from inflammatory reactions, which were not demonstrated in salinomycin-treated birds. The B&O supplementation increased (p < 0.05) the immune system by enhancing Eimeria-specific immunoglobulin Y titer and lymphocyte proliferation response. This study suggests that the combined application of OEO and BA can substitute for a commercial anti-coccidial agent (salinomycin) in controlling coccidiosis as well as improving growth performance, gut health, and immune responses in broiler chickens with a means of antimicrobial-resistant free food products.

Pathological and pharmacovigilance monitoring as toxicological imputations of azithromycin and its residues in broilers.

The importance of monitoring antimicrobial residues in food is underlined by increasing worries about food safety and public health. The potential toxicity of azithromycin (Az) on broilers and its impact on chicken meat residues require further investigation. This study assesses Az's toxicity effects and associated risks in broiler chickens through evaluation. One hundred and twenty chicks were distributed into four equal groups randomly. Each group received different daily oral doses of Az: 200 mg/kg for Az1, 100 mg/kg for Az2, and 50 mg/kg for Az3. The FAz group was given plain water. High-performance liquid chromatography was used to measure Az residue levels in muscle and liver. Oxidative markers (malondialdehyde [MDA], superoxide dismutase [SOD], catalase [CAT]), liver and kidney function tests, and histopathological examination were conducted. The levels of alanine aminotransferase and aspartate aminotransferase increased in Az1 and Az2 groups from 8 h to 3 days and decreased slightly in Az2 by 7 days, while they remained normal in Az3. The levels of uric acid and creatine in the Az1 and Az2 groups increased from 8 h to 3 days and subsequently decreased in Az2 by the 7th day. Az1 group showed the highest increase in MDA levels within 7 days. With higher Az doses, SOD and CAT levels showed a more significant decrease post-treatment. 9.1 μg/kg Az1 liver had the highest residues, whereas none were detected in muscle. At higher doses, Az caused significant liver and kidney damage, whereas lower doses had negligible effects. Muscle tissue contains fewer Az residues than liver. Assessing risks and ensuring compliance with regulations necessitate constant surveillance of Az residues in food. The health implications and risk management insights necessitate further investigation into the long-term effects of Az residues.

Determination of Sulphonamides and Tetracycline Residues in Liver Tissues of Broiler Chicken Sold in Kinondoni and Ilala Municipalities, Dar es Salaam, Tanzania.

In Tanzania, the increased demand for animal-derived foods, particularly eggs, meat, and milk, has resulted in the intensification of farming systems with the use of antimicrobials, particularly sulphonamides and tetracyclines. According to the FAO/WHO Codex Alimentarius commission, concentrations of antimicrobial residues in food exceeding the acceptable daily intake (ADI) and maximum residual limit (MRL) pose a health risk to consumers. This cross-sectional study determined the concentrations of sulphonamide and tetracycline residues in the liver tissues of commercial broiler chicken sold in Dar es Salaam, Tanzania, to find out whether the amounts of residues were within the legally permitted and acceptable limits in food. We conveniently sampled eighty-four liver tissue samples from broiler chicken sold in two out of six large markets in Dar es Salaam. The amounts of tetracycline and sulphonamide residues were determined using an ELISA kit (Shenzhen Lvshiyuan Biotechnology Company, Shenzhen, China). The results showed that all 100% (n = 84) samples contained tetracycline residues and 21.4% (n = 18) samples contained sulphonamide residues, while 21.4% (n = 18) contained both sulphonamide and tetracycline residues. The concentrations of sulphonamide residues were within the maximum residual limit (MRL). However, 90.5% (n = 76) of the samples had tetracycline levels that exceeded the acceptable daily intake (ADI) range 0–3 µg/kg and 13.1% (n = 11) of the samples had tetracycline levels that exceeded the maximum residue limit of 300 µg/kg. The observed presence of antibiotic residues in the poultry tissues poses a health risk to consumers, and may lead to antimicrobial resistance micro-organisms, which may spread to humans and animals via the environment. Vigorous surveillance and observation of the withdrawal periods should be advocated to ensure that the food from animals is safe with regard to the residues of veterinary medicines.

Impact of Chronic Tetracycline Exposure on Human Intestinal Microbiota in a Continuous Flow Bioreactor Model.

Studying potential dietary exposure to antimicrobial drug residues via meat and dairy products is essential to ensure human health and consumer safety. When studying how antimicrobial residues in food impact the development of antimicrobial drug resistance and disrupt normal bacteria community structure in the intestine, there are diverse methodological challenges to overcome. In this study, traditional cultures and molecular analysis techniques were used to determine the effects of tetracycline at chronic subinhibitory exposure levels on human intestinal microbiota using an in vitro continuous flow bioreactor. Six bioreactor culture vessels containing human fecal suspensions were maintained at 37 °C for 7 days. After a steady state was achieved, the suspensions were dosed with 0, 0.015, 0.15, 1.5, 15, or 150 µg/mL tetracycline, respectively. Exposure to 150 µg/mL tetracycline resulted in a decrease of total anaerobic bacteria from 1.9 × 107 ± 0.3 × 107 down to 2 × 106 ± 0.8 × 106 CFU/mL. Dose-dependent effects of tetracycline were noted for perturbations of tetB and tetD gene expression and changes in acetate and propionate concentrations. Although no-observed-adverse-effect concentrations differed, depending on the traditional cultures and the molecular analysis techniques used, this in vitro continuous flow bioreactor study contributes to the knowledge base regarding the impact of chronic exposure of tetracycline on human intestinal microbiota.

Antimicrobial Residues in Food from Animal Origin-A Review of the Literature Focusing on Products Collected in Stores and Markets Worldwide.

The extensive use of antibiotics leads to antibiotic residues in frequently consumed foods. Generally, the main use of antibiotics in animals is to treat and prevent diseases and growth promotion. However, the residues and their breakdown products have several side effects on the human body and, in a broader sense, on the environment. In relation to the human body, the frequency of mutations is increased, the bone marrow is damaged (chloramphenicol), and the reproductive organs of humans are affected. Carcinogenic effects have been found with antibiotics such as sulfamethazine, oxytetracycline, and furazolidone. We summarized data from 73 scientific studies reporting antimicrobial residues in animal products that were freely available for sale. The studies were published in English starting from 1999 till 2021 and identified through the Pubmed search engine. The aims were to find out which antibiotics, legal or illegal, could be found in animal foods worldwide. Which are stable to get into the food chain and exceed the maximum residue limits (MRL) regarding the EU guidelines as a comparison. Reducing antimicrobial residues in food from animal origin and, in addition to this, fighting the tremendous growth and spread of antimicrobial resistance will undoubtedly be one of the most difficult food safety challenges in the coming years.

Contribution of Nanomaterials to the Development of Electrochemical Aptasensors for the Detection of Antimicrobial Residues in Food Products

The detection of antimicrobial residues in food products of animal origin is of utmost importance. Indeed antimicrobial residues could be present in animal derived food products because of animal treatments for curative purposes or from illegal use. The usual screening methods to detect antimicrobial residues in food are microbiological, immunological or physico-chemical methods. The development of biosensors to propose sensitive, cheap and quick alternatives to classical methods is constantly increasing. Aptasensors are one of the major trends proposed in the literature, in parallel with the development of immunosensors based on antibodies. The characteristics of electrochemical sensors (i.e., low cost, miniaturization, and portable instrumentation) make them very good candidates to develop screening methods for antimicrobial residues in food products. This review will focus on the recent advances in the development of electrochemical aptasensors for the detection of antimicrobial residues in food products. The contribution of nanomaterials to improve the performance characteristics of electrochemical aptasensors (e.g., Sensitivity, easiness, stability) in the last ten years, as well as signal amplification techniques will be highlighted.

A SIX PLATE MICROBIOLOGICAL ASSAY FOR SCREENING OF ANTIMICROBIAL RESIDUES IN FOOD OF ANIMAL ORIGIN

Occurrence of antimicrobial residues in livestock and aquatic products is a current public health concern. The monitoring of food commodities for antimicrobial residues will ensure the consumer safety and promote trade. Therefore, the objective of this study was to establish a screening test to detect antimicrobial residues in food of animal origin. A bioassay consists of six plates was established, which enables screening of six groups of antimicrobials, namely; penicillins, sulphonamides, streptomycin, erythromycin, tetracyclines and fluroquinolones. The Six Plate Test (SPT) is a bioassay technique, which is carried out using Bacillus subtilis BGA (Merck), Bacillus cereus (ATCC 11778), Micrococcus luteus (ATCC 9341) and Escherichia coli (ATCC 11303) as indicator organisms. The Mueller Hinton Agar (MHA) was used as the test medium at optimum pH for all indicator organisms except B.cereus, for which the Media No.8 was used. The Minimum Detectable Concentrations (MDC) of SPT were determined using serial dilutions of antibiotics. All the MDC values obtained on SPT for the validated antimicrobials were below the recommended MRL of each antimicrobial. SPT can be developed to a quick, easy to perform, robust and low cost screening test to detect antimicrobial residues in food of animal origin.

Screening of Antimicrobial Residues among Table Eggs Using Disc Diffusion Assay at Erbil Governorate, Kurdistan Region, Iraq

The existence of antimicrobial residues in food of animal origin is a safety concern worldwide. This study investigated the occurrence of such residues in table eggs collected from Erbil city (Iraq) markets according to shell color, location, and season. Results showed that the total proportion was 15.2%. The differences were not significant for the shell color (White color 13.7%; Brown color 16.8%), location (Urban 16.4%; Rural 13.8%), and months (July 12.1%, August 13.5%, September 18.8%, October 15.7%, December 16.9%, and November 14.1%). Such level of residue contamination requires a response from in-charge Iraqi health authorities to regulate antibiotics usage and ensure food safety.

Does Dietary Consumption of Antibiotics by Humans Promote Antibiotic Resistance in the Gut Microbiome?

Mandated authorities have developed principles for evaluating the safety of antimicrobial residues in food and have established microbiological acceptable daily intakes (ADIs) and recommended maximum residue limits (MRLs) for antibiotic residues in food products. The evaluation of the ADI is based in relevant scientific information such as MIC data of predominant human intestinal bacteria. However, it does not include data derived from minimal selective concentration (MSC) predictions that estimate the lowest concentration of an antibiotic that will provide resistant bacteria an advantage over susceptible bacteria. Based on these insights, we sought to determine whether human exposure to selected antibiotics through ingestion of foodstuffs could result in colon concentrations exceeding apparent MSCs. Nine antibiotics-tetracycline, oxytetracycline, ciprofloxacin, sarafloxacin, erythromycin, spiramycin, tilmicosin, tylosin, and lincomycin-were selected for analysis. Dietary exposure was estimated either using published measured antibiotic concentrations in foodstuffs or using ADI values or food MRLs and a conservative diet. Using the ADI, the estimated antibiotic residue concentrations in the human colon of all antibiotics assessed may be up to a 1,000-fold greater than the predicted MSCs. When the dietary exposure assessment used MRLs or measured concentration in foodstuffs, the estimated concentrations were considerably lower but still within the MSC range for most of the foodstuffs assessed. These results suggest that the ingestion of antibiotic residues through food consumption may expose intestinal microbiota to antibiotic concentrations exceeding the MSC boundaries, thus favoring the growth of potential resistant bacteria. We suggest that MRL and ADI values be revisited in light of the recognition that antibiotic concentrations significantly below the MIC may select for resistance.

Proficiency testing as an instrument to assess the analytical performance and the methods routinely implemented: the Italian experience for the screening of antibiotic residues in milk in the official control

The present work describes the outcome of the second proficiency test (PT) for the routine screening of antibiotic residues in milk, organized in 2016, for the Official Control Laboratories by the National Reference Laboratory (NRL) for veterinary antimicrobial residues in food of animal origin (ISS, Italy). Besides assessing the overall laboratories’ performance, this PT aimed to update the information concerning the screening methods used at the national level and focused, in particular, on the Official Control Laboratories performance for the detection of tetracyclines. This last feature intended to tackle the strong criticalities observed in the first PT, organized by the NRL in 2012, and to monitor the consequent implementation of relevant corrective actions. Thirty-one Official Control Laboratories joined the 2016 PT. They received five lyophilized milk samples, one negative and four positive for benzylpenicillin (PEN), sulphadiazine (SDZ) and oxytetracycline (OXY) to be reconstituted to the final concentrations of 1×MRL for PEN and SDZ and 2.5× and 4×MRL, respectively, for OXY. In addition, only for OXY, the protocol required the preparation by dilution of two additional samples at the final concentrations of 2× and 1×MRL. Overall the laboratories’ performance was satisfactory. However, for OXY, although a reduction in the percentage of false negative results was observed, as compared to the first PT, the majority of laboratories had not yet implemented complementary methods to respond to the criticality previously signalled. One more time the organization of a dedicated PT proved to be an effective means to provide objective indicators of the state of the art in a specific area of testing.

Rapid screening of multi-class antimicrobial residues in food of animal origin by paper spray mass spectrometry

Antibiotics monitoring is of importance in providing healthy diets by preventing animal husbandry from antibiotic misuse. The development of paper spray provides a time-efficient strategy to analyze antibiotics in complex matrices without sample preparation. In this work, paper spray mass spectrometry was applied to identify and quantify nine antimicrobial residues in four antimicrobial families from four kinds of general food matrix, including beef, chicken meat, milk and egg. Samples were directly placed on the paper without any further sample treatment. The limits of detections (LODs) were obtained as 15.0 μg/kg for marbofloxacin in chicken meat, 15.0 μg/kg for difloxacin in chicken meat, 12.5 μg/kg for lincomycin in beef, 12.5 μg/kg for clindamycin in beef, 4.0 μg/kg for amoxicillin in milk, 4.0 μg/kg for penicillin-G in milk, 10.0 μg/kg for cloxacillin in milk, 12.5 μg/kg for minocycline in egg, and 6.2 μg/kg chlortetracycline in egg, respectively. All the LODs were in accordance with the restriction of maximum residue limits (MRLs) of antimicrobial residues announced by the Council Regulation 2377/90/EEC, which suggests a sufficient capability of the paper spray mass spectrometry (PS-MS) method to rapidly screen antimicrobial residues in foods of animal origins.

Antimicrobial residues and compositional quality of informally marketed raw cow milk, Lamu West Sub-County, Kenya, 2015.

Introductionunadulterated milk, free of antimicrobial residues is important for industrial processing and consumers’ health. Antimicrobial residues in foods of animal origin can cause adverse public health effects like drug resistance and hypersensitivity. Milk produced in Lamu West sub-county is sold raw directly to consumers. We estimated the compositional quality and prevalence of antimicrobial residues in informally marketed raw cow milk in Lamu West Sub-County, Kenya.Methodswe randomly recruited 152 vendors and 207 farmers from four randomly selected urban centers in a cross-sectional study and interviewed them using a pretested standardized questionnaire. A100-ml raw milk sample was aseptically collected from each vendor and farm and tested for antimicrobial residues using Charm Blue Yellow II kit following the European Union Maximum Residue Limits (EU-MRLs) while an Ekomilk® Analyzer was used to measure compositional quality where samples with either solid not fat (SNF) < 8.5 or added water ≥ 0.01% or both were considered adulterated. We analyzed data using univariate analysis and unconditional logistic regression to calculate odds ratios (OR) and 95% confidence intervals (CI).Resultsthirty-two of the 207 (15.5%) samples from farmers and 28 (18.4%) of the 152 samples from vendors tested positive for antimicrobial residues. Thirty-six (17.4 %) samples from farmers and 38 (25.0%) from vendors were found to be adulterated with water. Farmers’ awareness of the danger of consuming milk with antimicrobial residues and farmers having training on good milking practices were protective against selling milk with antimicrobial residues (adjusted OR and 95% CI 0.20, 0.07-0.55 and 0.33, 0.11-0.99, respectively).Conclusionthe antimicrobial residues above EU MRLs and adulteration of raw marketed cow milk observed in this study provide evidence for routine testing of marketed milk and educating farmers to observe antimicrobial withdrawal period.

PT as a tool to point out criticalities in the strategy for control of antibiotic residues in milk: the Italian experience

Screening represents the first step for antibiotic residues control; thus, screening methods play a key role in the entire control procedure. The Italian National Reference Laboratory (NRL) for veterinary antimicrobial residues in food from animal origin organized the first proficiency test (PT) for the screening of antibiotic residues in milk to assess the competence of the official control laboratories. The 38 participants received two series (respectively, at 1.8 % and 3.5 % of fat mass fraction) of eight blind lyophilized milk samples, spiked with cloxacillin (CLX), benzylpenicillin (PEN), sulfadiazine (SDZ) and oxytetracycline (OXY) at once and twice the respective maximum residue limit. In addition, an unspiked sample (blank) was also included in each series. Since the vast majority of false-negative results was associated with OXY, leading to low sensitivity and accuracy, laboratories performances were evaluated separately for OXY (sensitivity 16.44 %, false-negative rate 62.25 % and accuracy 44.54 %) and, respectively, for CLX, PEN and SDZ assessed together (sensitivity 99.56 %, false-negative rate 2.53 % and accuracy 99.63 %); the false-positive rate resulted equivalent to 0 % and the specificity to 100 %. The criticality identified by the PT was that OXY was not detectable under the routine screening analysis conditions adopted because of the use of only two screening methods (Delvotest SP-NT and CMT) both unfit for its detection at mass fractions of interest. As a consequence, the NRL provided guidance to participants to implement different and complementary screening methods. The effectiveness of the corrective actions undertaken by participants will be evaluated with the next PT.

Résidus d’antibiotiques et denrées d’origine animale en Afrique : risques de santé publique

The authors report on the current status of work on residues of veterinary medicinal products and, in particular, antimicrobial residues in foods of animal origin. This review focuses on residues of veterinary antimicrobials, antimicrobials used in livestock production, the concept of residues, and antimicrobial residues in foods of animal origin. Only one antimicrobial substance has been approved in the West African Economic and Monetary Union, compared with 16 substances in Benin and 56 in the European Union. The issue of antimicrobial residues in foods of animal origin has rarely been a serious concern in developing countries, in contrast to the situation in Europe. However, while the prevalence of veterinary drug residues in foods of animal origin is less than 1% in Europe, in some African countries it can be as high as 94%. Antimicrobial residues in foods of animal origin can cause allergies, cancer, alterations in the intestinal flora, bacterial resistance and the inhibition of fermentation in the dairy industry. The harmonisation of regulations in Africa could reduce the circulation of prohibited antimicrobials and lead to the implementation of a plan for the control and surveillance of residues from veterinary medicinal products in foods of animal origin.

English

Worldwide laws are being created to reduce the amount of antimicrobial residues in foods and beverages. Distilled alcoholic beverages, such as cacha&ccedil;a should be detached, because some microorganisms infect the fermentation process and decrease the product quality, making it to require microbiological control. Thus, the objective of this research was to evaluate the green and brown propolis extract, as well as the previous physical-chemical treatment of sugarcane juice as antimicrobial agents and their effects on yeast CA-11 fermentation for cacha&ccedil;a production. The experiment was arranged in a completely randomized design in split splots with three replications. Main treatments constituted four antimicrobials (sodium monoensin, green propolis extract, brown propolis extract and physical-chemical treatment) and an untreated control. Secondary treatments were the five fermentation cycles. The amount of yeast cell and bud viability, yeast bud rate during the fermentation, pH, total acidity, glycerol and alcohol contents were evaluated in wines. The use of antimicrobial agents, especially the green and brown propolis extracts, improved the maintenance of the amount of live yeast cells and buds, and yeast budding rate as compared to the control treatment. Ethanol levels produced by the yeast strain &lsquo;CA-11&rsquo; during fermentation were found to be around 6 to 7%, which are not statistically significant among the treatments. Results indicate great potential for the use of propolis as antimicrobial in fermentatiton process for production of distilled beverages, like cacha&ccedil;a. Key words: Distillate beverages, cacha&ccedil;a, antimicrobial agents, Saccharomyces cerevisiae.

Effect of sterilized human fecal extract on the sensitivity of Escherichia coli ATCC 25922 to enrofloxacin

The ingestion of antimicrobial residues in foods of animal origin has the potential risk of exposing colonic bacteria to small concentrations of antibiotics and inducing resistance in the colonic bacteria. To investigate whether human intestinal contents would influence resistance development in bacteria, Escherichia coli ATCC 25922 (MIC of enrofloxacin <0.03 μg ml(-1)) was exposed to 0.01 to 1 μg ml(-1) of enrofloxacin in media supplemented with glucose, sucrose, sodium acetate or sterilized human fecal extract. In the first passage, only the medium containing sterilized fecal extract supported the growth of E. coli at an enrofloxacin concentration equal to the MIC. In the second and third passages following exposure to sub-inhibitory concentrations of the drug, the bacteria in media containing sterilized fecal extract grew at 0.1 μg ml(-1) of enrofloxacin. The efflux pump inhibitors, reserpine and carbonyl cyanide-m-chlorophenylhydrazone (CCCP), increased the sensitivity of bacteria to 0.1 μg ml(-1) of enrofloxacin in the medium containing sucrose, but their effect was not observed in the medium supplemented with 2.5% sterilized fecal extract. The proportions of unsaturated and saturated fatty acids in E. coli grown in the medium with 2.5% sterilized fecal extract differed from those grown in the medium alone. Fecal extract may contain unknown factors that augment the ability of E. coli to grow in concentrations of enrofloxacin higher than MIC, both in the presence and absence of efflux pump inhibitors. This is the first study showing that fecal extract affects the level of sensitivity of E. coli to antimicrobial agents.

Performance of a New Microbial Test for Quinolone Residues in Muscle

Concerns regarding the presence of drug residues in foods include allergic reactions, toxicity, technological problems in fermented products and the development of antibiotic resistance in human pathogens. The analysis of antimicrobial residues in foods is generally carried out, in a first step, through microbiological screening tests. These tests commonly use Geobacillus stearothermophilus as target specie but show a low ability to detect quinolones. The goal of our study was to evaluate the performance of a new microbiological test (Equinox) for detection of quinolone residues in muscle. The kit contains an ampoule with a standardized number of freeze-dried Escherichia coli and must be diluted with a specific detection medium containing a redox indicator. Microbial growth will modify the redox potential of the medium being observed through a colour change (from blue to brown/orange). Equinox limits of detection for most of tested quinolones (enrofloxacin, norfloxacin, sarafloxacin, marbofloxacin, ciprofloxacin, danofloxacin and difloxacin) were below or around maximum residue limit (MRL) UE and CCβ values obtained corresponded with the determined sensitivities. In contrast, flumequine could not be detected at MRL UE levels. Moreover, Equinox displayed a low sensitivity to other antimicrobials. Sensitivity data obtained in vitro were consistent when testing incurred muscle samples. Matrix constituents, test batch and animal species did not affect the performance of the test. Equinox could be easily automated enabling a large numbers of simultaneous analysis, and a photometric reading can be applied for a precise interpretation. The results obtained in this study prove that Equinox is a useful tool when screening for quinolone residues or can be combined with other methods for screening of unknown samples.

European proficiency testing of national reference laboratories for the confirmation of sulfonamide residues in muscle and milk

Two interlaboratory studies were organized in 2002–2003 in order to check the proficiency of laboratories in confirming the presence of sulfonamide residues in muscle and milk. These studies involved 25 EU National Reference Laboratories (NRLs) from 21 different European countries in charge of statutory monitoring of antimicrobial residues in food of animal origin at a national level. The study was conducted according to international and national guidelines by the Community Reference Laboratory (CRL) in charge of antimicrobial substances. Four different test matrices of sheep muscle and four different test matrices of bovine milk containing different sulfonamide substances were prepared and sent to the participants. Each participant was asked to use his own routine confirmatory method and to analyse each sample in triplicate within a period of about six weeks during which the stability of the materials was checked by the organizer. The sulfonamide content of each material was determined by calculating the robust means of all the results and the deviation of the results from the assigned values was assessed by calculating Z-scores. Overall, results were satisfactory, particularly considering that it was the first proficiency test dealing with sulfonamides organised by the Community Reference Laboratory.

Historical Perspective on the Regulation of Antimicrobial Residues in Food

When we think about international regulation of veterinary drug residues in foods, three entities come to mind. These are the Codex Alimentarius Commission (CAC), the European Medicines Evaluation Agency (EMEA) and the Veterinary International Cooperation on Harmonization (VICH). Because this workshop is more scientific than regulatory in nature, the history and activities of the scientific advisory bodies that serve these entities will be described. These are the Joint FAO:WHO Expert Committee on Food Additives (JECFA), the Committee for Veterinary Medicinal Products and the Safety Working Group. These scientific working groups provide support to the CAC, EMEA and VICH, respectively, on matters related to the safety of veterinary drug residues in food and the appropriate tests needed to determine safety.

Historical Perspective on the Regulation of Antimicrobial Residues in Food in the United States

In the US, antimicrobials used in animals for both therapeutic and growth promotion purposes are considered animals drugs. Antimicrobial drugs are used in animals to treat and prevent disease, and to increase production. Before any animal drug can be legally marketed in the US, the drug’s sponsor must have a New Animal Drug Application (NADA) approved by the Food and Drug Administration (FDA). Within FDA, the Center for Veterinary Medicine (CVM) is responsible for determining when an animal drug is effective and safe for the animal, the environment and can be manufactured to uniform standards of purity, strength and identity. When the animal drug is intended for use in food-producing animals, the drug sponsor must also demonstrate that edible products from the treated animals are safe for consumers (1). While CVM is responsible for performing the safety assessment for animal drug residues, the United States Department of Agriculture (USDA), Food Safety Inspection Service is responsible for testing the meat supply for microbiological contamination and animal drug residues. Both FDA and USDA have extensive programs to ensure that meat, milk and other animal products are safe and wholesome.