Web-based Korean maximum residue limit evaluation tools: an applied example of maximum residue limit evaluation for trichlorfon in fishery products

To ensure public safety against veterinary drug residues in food products from animal sources, maximum residue limits (MRLs) should be established by scientific evidence and a transparent estimation process. The Joint Food and Agriculture Organization (FAO)/World Health Organization (WHO) Expert Committee on Food Additives (JECFA) developed an Excel workbook-based tool for MRLs evaluation in 2003. In this study, we developed a web-based tool for MRL evaluation, called Korean MRL evaluation tools (KMET). While KMET used algorithms of JECFA workbook, it added some databases (e.g., Korean food consumption database) and provided additional functions (e.g., selection of target marker residue). Web-based KMET enabled regulatory policy makers to update the database. All input data and output results related to MRL evaluation based on residue depletion and food consumption datasets were archived and provided overall processes from the initial depletion data entry to MRL establishment with user-friendly interface. Our results demonstrated the stepwise processes whereby MRL for trichlorfon in the muscle of Paralichthys olivaceus was established with functional descriptions of KMET. MRL for trichlorfon derived from KMET was proposed and notified by the Ministry of Food and Drug Safety in 2018.

Validation of the betaeta-s.t.a.r. 1 + 1 for rapid screening of residues of beta-lactam antibiotics in milk

The 2-min protocol (1 + 1) for the betaeta-s.t.a.r. (manufactured by Neogen Corporation, Lansing, MI, USA) was validated at the Technology and Food Science Unit of the Institute for Agricultural and Fisheries Research according to Commission Decision 2002/657/EC. The test was very selective for the group of beta-lactam compounds: the only interference found was by clavulanic acid at 2500 microg kg(-1) and above. The modified protocol (betaeta-s.t.a.r. 1 + 1) detected all beta-lactams with a maximum residue limit (MRL) in milk, but not all these compounds were detected at their respective MRL. The detection of cefalexin (detection capability = 6000 microg kg(-1); MRL = 100 microg kg(-1)) and penethamate (detection capability = 80 microg kg(-1); MRL = 4 microg kg(-1)) was especially poor, and also ceftiofur was only detected from 500 microg kg(-1) (MRL = 100 microg kg(-1)). The repeatability of the reader and of the test was very good. The test was very robust: test results were not significantly influenced by small changes in the test protocol, by the milk composition or by the type of milk. The test was also suitable to test the milk of animal species other than cow. Favourable results were obtained in testing monitoring samples, in two national ring trials, and in an international proficiency test. The betaeta-s.t.a.r. 1 + 1 is a very fast, simple, and reliable test that could be used at the farm level to prevent tanker milk contamination by beta-lactams.

Impact of antimicrobial residues on gut communities: are the new regulations effective?

Veterinary medicines are subject to a rigorous evaluation with regard to safety, efficacy and quality before they are licensed. For drugs used in food producing animals, it is necessary to establish what is referred to as the acceptable daily intake (ADI), this is defined as an estimate of the amount of a substance, expressed on a body weight basis, that can be ingested daily over a lifetime without appreciable risk to human health. It is necessary to determine a toxicological, pharmacological and microbiological ADI. This article describes a recently harmonized guideline that outlines the process for determining the need for a microbiological ADI and discusses the test systems that take into account the complexity of the human intestinal flora. The described process is used to address the effects of antimicrobial drug residues on human intestinal flora for regulatory purposes. The guideline does not recommend any one particular system for use in regulatory decision making but provides recommendations for a harmonized approach to establish a microbiological ADI and offers test options rather than specifying a testing regimen. The process and the challenges of this new guideline are discussed.

The joint food and agriculture organization of the United Nations/World Health Organization Expert Committee on Food Additives and its role in the evaluation of the safety of veterinary drug residues in foods

The Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO) recommended the evaluation of food additives at the international level through the establishment of an expert committee or committees. These committees evaluated the safety of food additives present as residues resulting from the use of pesticides or veterinary pharmaceuticals. The results of these meetings include international harmonization on acceptable daily intake of these compounds and the maximum residue limit that is permitted to be present within any food of animal or plant origin. The decisions rendered by these committees provide a key element in the elimination of international trade barriers associated with products intended for human consumption.

Demystifying 21 CFR Part 556—Tolerances for residues of new animal drugs in food

21 Code of Federal Regulations Part 556 (Tolerances for Residues of New Animal Drugs in Foods) is one of the Center for Veterinary Medicine's most significant set of regulations. However, in many respects, it is outdated. Subpart A (General Provisions) defines tolerance designations that are obsolete, while Subpart B (Specific Tolerances for Residues of New Animal Drugs) is inconsistent in terminology and often confusing. The purpose of this paper is to define the older terms and update the reader as to current concepts that apply to tolerance-setting for new animal drugs. A list of useful definitions appears at the end of the article.

Approaches in the safety evaluations of veterinary antimicrobial agents in food to determine the effects on the human intestinal microflora

The administration of antimicrobial agents to livestock creates potential for antibiotic residues to enter the food supply and be consumed by humans. Therefore, as a process of food animal drug registration, national regulatory agencies and international committees evaluate data regarding the chemical, microbiologic, pharmacokinetic, pharmacodynamic, pharmacologic, toxicologic, and antimicrobial properties of veterinary drugs to assess the safety of ingested antimicrobial residues to consumers. Currently, European, Australian and United States guidelines for veterinary drug registration require a safety assessment of microbiologic hazards from consumption of antimicrobial residues taking into account the potentially adverse effects on human intestinal microflora. The main concerns addressed are selection of resistant bacteria in the gastrointestinal tract and disruption of the colonization barrier of the resident intestinal microflora. Current requirements differ among national agencies. Efforts are ongoing internationally to review and harmonize approaches and test methods and protocols for application to these microbiologic safety evaluations of antimicrobial drug residues in food. This review describes the background to current regulatory approaches used in applying in vitro and in vivo methods to set a microbiologic acceptable daily intake for residues in food derived from animals treated with an antimicrobial agent. This paper also examines the current research needs to support these evaluations.

Estimating provisional acceptable residues for extralabel drug use in livestock

In 1996, the United States Congress passed legislation (Animal Medicinal Drug Use Clarification Act, AMDUCA), which allows some veterinary or human drugs to be used off label in food-producing animals. In order to implement this Act and protect the U.S. consumer, tolerances or safe concentrations are required before a withdrawal time can be estimated for extralabel drug use. Use of foreign MRLs to satisfy these data needs may not be applicable because of differences in safety standards between the U.S. and other countries. This paper presents strategies that can be used to derive equivalent safe concentrations, referred to as provisional acceptable residues (PARs), that may then be used to estimate drug withdrawal times. Health-based methods are proposed for calculating a PAR for a tissue. Procedure A partitions 50% of the acceptable daily intake (ADI) to edible tissues and reserves the remainder for milk. Procedure B equally partitions the ADI into all edible tissues. Procedure C partitions 50% of the ADI to milk and equally partitions the remaining 50% ADI into edible tissues. Simulations were performed for florfenicol, tetracycline, dexamethasone, azaperone, ivermectin, eprinomectin, and doramectin. In general, these simulations resulted in derivation of conservative PARs, which did not result in daily intakes of residues greater than the health-based ADI. These simulations demonstrated that provided the safe concentrations or equivalent PARs are based on rigorous toxicology safety data (e.g., NOELs, ADIs), the safety of food animal products will not be compromised. It is proposed that these PARs can be used for estimating withdrawal times after extralabel drug use or inadvertent exposure to an environmental contaminant where no approved withdrawal time exists. Finally, implementing similar transparent methods could have a positive impact on international harmonization and trade.

Dietary intake estimates as a means to the harmonization of maximum residue levels for veterinary drugs. I. Concept

The harmonization of standards and procedures for establishing tolerances or maximum residue levels (MRLs) for veterinary drug residues in edible animal products is a major goal of the international veterinary drug community. Such harmonization would contribute to easing trade barriers. This paper proposes use of the toxicologically determined acceptable daily intake (ADI) for the drug as the safety standard for reaching conclusions on the acceptability of residues in meat for human consumption. Specifically, the 'equivalence' of different MRLs for the same veterinary drug would be determined by considering whether they are likely to result in dietary residues that exceed another country's ADI for the drug. Two methods of estimating dietary intake are described, and estimates are made for the veterinary drugs albendazole and ivermectin. Based on these estimates, the US and JECFA MRLs for each drug would be considered 'equivalent' for trade purposes.

Establishment of a microbiologically acceptable daily intake of antimicrobial drug residues

A model is presented to calculate the microbiologically acceptable daily intake (ADIm) of antibiotic residues in food products. The ADIm calculation is based on MIC values for indicator bacteria Escherichia coli, Bacteroides fragilis, Bifidobacterium spp. and Eubacterium spp., established under gut-like conditions in an in vitro simulation model. The maximum residue level (MRL) for residues in food products can be derived from the ADIm. Four phases can be distinguished in this gastro-intestinal simulation model, namely: 1. In vitro determination of the MIC for each bacterial strain by a standard method. 2. Incorporation of the drug into food (meat, milk) followed by testing of the stability of the antibiotic under gut-like conditions. 3. Adjustment of the 'gastric' fluid to the duodenal situation, inoculation with the test bacteria and anaerobic incubation at 37 degrees C for at least 18 h. 4. MIC reading confirmed by counting bacteria growing on specific solidified media. In this study the method for calculation of ADIm and MRL is given for flumequine as model drug. On the basis of MIC50 values for E. coli strains, a MRL for flumequine of 1.0 microgram/g meat or 0.25 microgram/ml milk was calculated. It is suggested that, depending on the antibacterial spectrum of the antibiotic involved, the ADIm can be determined with selected indicator bacteria, incubated under simulated gastrointestinal conditions.

An update on ethylene oxide sterilization issues

The regulations governing ethylene oxide sterilization are becoming clearer with the appearance of European standards for validation and routine control of the process. In addition, the process has undergone technological changes in recent years. In this article, the author outlines the developments that have taken place in the areas of residue reduction, biological indicators, and emission control and suggests further improvements that would ensure its place as the principle method of sterilization for the twenty first century.

Compliance with recommended drug withdrawal requirements for dairy cows sent to market in Michigan

By examination of computerized individual cow records from January 1981 through June 1985, compliance with premarketing drug withdrawal times was investigated in 23 dairy herds. During this period, 877 cows were culled from 23 herds; 33 cows from 12 herds were in violation of premarketing drug withdrawal times. Six herds had 1 violation, 2 herds had 2 violations, 2 herds had 3 and 4 violations, and 2 herds had 7 and 9 violations. Fifty drugs had been used; 15 drugs were used in violation of drug withdrawal times before cows were sent to market. The most commonly used drugs in violation were oxytetracycline, gentamicin, chloramphenicol, and a combination of lincomycin/spectinomycin. Significant differences between cows in violation and cows not in violation were not observed for age, lactation number, milk production, herd size, or month of culling. However, the 12 herds in violation of premarket drug withdrawal times had significantly (P less than 0.05) more cows culled within 30 days for retained placenta and milk fever, and more cows culled within 30 and 100 days for mastitis, metritis, and displaced abomasum. Although not significant, the 2 herds with 7 and 9 violations had more hired vs family labor than did the other herds with violations.

USDA regulation of residues in meat and poultry products

The National Residue Program conducted by the Food Safety and Inspection Service (FSIS) of the USDA includes a comprehensive testing program for residues of pesticides, drugs and other chemical contaminants in meat and poultry. Prevention strategies encourage producers to adopt quality control measures in their production management to prevent illegal residues in food. These activities have been effective in reducing the occurrence of violative residues and the potential for adverse health effects. Overall, the number of domestic monitoring samples containing violative residues is low-about 1% of samples tested. Violative residues are found less frequently in poultry than in livestock. More occur in swine than in other species; the least number occur in fed cattle and broilers. Testing results over the last 10 yr show that most drugs and pesticides used to enhance agricultural productivity are not causing a residue problem in meat and poultry. However, the FSIS cannot be complacent about its program achievements. Unacceptably high incidences of violative residues of certain drugs, namely, sulfonamides and antibiotics, still occur in particular production classes. For example, the incidence of violative sulfonamide residues in liver samples from swine slaughtered in 1985 was about 6%, with significant differences between geographical areas. An estimated 2.5% of market hogs had violative sulfamethazine residues in the muscle tissue. The FSIS is taking steps to correct this and other residue problems by strengthening the link between residue detection and enforcement and by expanding its analytical capability to monitor for residues.