Key findings:

Key findings highlight the importance of understanding factors influencing veterinary drug residues in food-producing animals, including drug administration, metabolism, and excretion, as well as the concept of bioactive excretion of pharmacologically active substances in animal waste and their potential environmental impacts, to effectively manage veterinary drug residues and their consequences.

What is known and what is new?

What is known is that sanitation and WASH (Water, Sanitation and Hygiene) are important global public health issues. What is new is the detailed data on the current state of global sanitation, with 57% of the population using safely managed sanitation services, and the identification of areas for further improvement to achieve universal access to adequate and equitable sanitation.

What is the implication, and what should change now?

The implication is that labetalol may be the preferred antihypertensive medication for managing hypertensive disorders of pregnancy due to its superior tolerability and similar efficacy compared to nifedipine. Changes needed include further research to confirm these findings and potentially update clinical guidelines to prioritize labetalol as the first-line treatment option for hypertension in pregnancy

In most countries, antimicrobial drugs are the most commonly used substances in livestock production. Other groups of drugs are used to a lesser degree and are linked mainly to protection against parasites and for growth promotion and feed efficiency. Veterinary drugs help maintain animal welfare by preventing and controlling animal diseases and promoting animal growth. However, the presence of relatively high concentrations of these drug residues in edible tissues from treated animals raises public health concerns for consumers over food and milk safety. This has resulted in different actions by the over 100 jurisdictions with laws regulating veterinary drug residues. Practice varies substantially among these jurisdictions, owing to the differences in laws, regulations, administrative positions, differences in production practices, lack of enforcement, and failures in producer concerns over drug residues. [1, 2]

1.1. Types of Veterinary Drugs

Just like humans, animals may become ill and need to receive antibiotic therapy. In the European Union, a veterinary antibiotic residue monitoring program is implemented where suspicious samples can be confirmed. In this way, controls for the entry of residues of veterinary drugs in the food chain are implemented. Slaughtered animals, milk, or other products are examined, and the presence of antimicrobial substances, including antibiotics, is tested. Authorizations for using veterinary medicines are given for specific purposes and for specific species. Only a small fraction of veterinary active substances may be applied for use in all food-producing animal species. All authorized veterinary drugs have different withdrawal periods to avoid accumulation in the animal organism. For this purpose, national laboratories and EU reference laboratories cooperate. Their main goal is the harmonization and equal treatment of control measures. Common strategies are the development and implementation of bio-analytical methods and the mass spectrometric identification of targets of biomarkers. The evaluation of the comparison studies of the laboratories is the basis for monitoring compliance at the national and European laboratory control levels. In this study, an attempt was made to present what types of veterinary drugs are used for animals, their side effects, and the danger of animal-origin meat and milk. [3, 4]

Antibiotics are used in preventing diseases and controlling various infections caused by pathogenic bacteria. Veterinary uses of antibiotics tend to lead to drug residues in the food products derived from these animals, such as meat and milk, which can harm consumers. Due to concentrations of drug residues in food obtained from animals being exposed to drugs during their life, several health problems have occurred. In 2015, the European Union introduced more stringent regulations for the presence of antimicrobial resistance in food. It sets limits for veterinary drugs that can cause allergic reactions or other toxicological, pharmacological, or microbiological problems. The European Union has developed methodologies and limits to maintain the health of consumers, which are presented in Annex I, para 5, of regulation 13/996. [5]

1.2. Regulations and Guidelines

Once these maximum levels are defined, regular monitoring is needed to detect and discard those products with unacceptable drug residues before they might be released for human consumption. For example, raw milk has to be checked for residues of each of the β-lactam antibiotics and tetracyclines as it is taken into a dairy plant. Dairy foods face stringent surveillance by regulatory agencies throughout the world such as the WHO, the U.S. FDA, and the European Food Safety Authority (EFSA). To meet international and national market requirements, changes in dairy cattle management and milk processing facilities are necessary to reduce the risk of meat and milk contamination by veterinary drug residues. Working directly with farmers, a number of extension programs have been developed to improve the daily management of livestock as part of the rural veterinarian's daily work. [6]

International regulations exist to provide consumers with maximum safety against drug residues and contamination in milk and meat. Maximum residue levels (MRLs) define the authorized threshold for a residue resulting from the use of a certain substance. In the EU, these are established on a scientific basis by the European Commission and defined for every veterinary drug and residue and their target tissues for all food-producing species. In the U.S., MRLs for approval are set by the U.S. Department of Agriculture's Food Safety and Inspection Service (FSIS). The Codex Alimentarius General Standard for Contaminants and Toxins in Food and Feed (STAN 193-1995) of the Codex Alimentarius establishes levels for contaminants, naturally present toxic substances, or those introduced by human activity (mycotoxins, heavy metals, and others) or intentionally added substances (food additives and veterinary drug residues). [7-9]

Milk and meat are valuable foods with high importance for nutritional needs. However, veterinary drugs used to prevent diseases among food animals can raise concerns about food safety. [10]

Also, veterinary drugs can lead to the evolution and proliferation of drug-resistant microorganisms when these drugs are used in food animals. Those drug-resistant microorganisms can then affect humans who consume the products from these animals. Chlortetracycline and erythromycin used to treat cattle wound infections can enter milk and affect the safety of the derived products. In cow treatment, residues of erysipelas vaccine products were detected in muscle and meat products. Data indicate that consumption of antibiotic-contaminated meat has led to therapeutic treatment failures in humans and subsequently has expanded the number of related illnesses, estimated to be related to thousands of illnesses with a cost of 167 million dollars. In this review, we summarized the influencing factors, impacted laws, and pharmacokinetic properties of drugs to enter into milk and meat based on different veterinary drugs. [11-12]

Veterinary drugs can enter the milk and meat of treated animals; humans may then consume a drug while they drink milk or eat meat. Such consumption may lead to the development of antibiotic resistance, which has serious consequences for human health. This is one of the main reasons why veterinary drug residues in milk and kidney are strictly limited in diverse countries by legislation. Physicochemical factors and pharmacokinetic properties contribute to the penetration of veterinary drugs into milk or meat. Optimal and short treatment periods can minimize the potential entrance of drugs into milk or meat and prevent the presence of residues in these locations. [13]

2.1. Mechanisms of Transfer

Data extrapolated from healthy animals treated with the maximum residue limits of veterinary medicines are the most active part of the foodstuff to consumers and should only rely on a very limited number of samples from foodstuffs. It would be better to monitor whether pharmacokinetic studies are complying with the legislated schemes. Where compliance seems unsatisfactory, both slaughter residues and residue testing of these foodstuffs. Such an approach could also be of great interest to the legislative authorities when deciding the withdrawal period for the use of a new veterinary drug or for a new administration route of an existing authorized veterinary drug. With limited resources to support the development of pharmaceutical research and maximize the regulatory resources, the results obtained from those studies should be considered in the scientific debate on MRLs [14].

General principles of pharmacokinetics are also available for veterinary drugs given to food-producing animals. This knowledge has been used to determine the ways in which veterinary drugs are transferred into foodstuffs of animal origin such as meat and milk, following administration to a food-producing animal. Knowledge and understanding of these transfer mechanisms are essential to assess the potential risks to consumers of consuming such food. High-quality data on tissue residues (meat, milk, eggs, tissues) are now available thanks to numerous experimental studies used to assess the food safety of veterinary drugs. Moreover, for substances such as residues of veterinary drugs, testing large numbers of samples using inappropriate methods can lead to unnecessary delays and additional costs to the pharmaceutical companies wishing to introduce new veterinary medicinal products [15, 16].

2.2. Factors Influencing Transfer

The described aspects of milk quality cannot be considered in isolation. Must be adapted to the characteristics of the local market and must respect the legal levels of residues [17].

The specific trade regime for milk from the residue-treated animal needs to be duly fulfilled. In practice, the value chain of the milk-dairy product is based on the safe quality and affordability of the consumed food, safe handling, avoiding drug-resistant microorganisms, and avoiding economic losses to both the farmer and the processor. The success of any drug program depends not only on the correct usage of a drug but also on its intrinsic characteristics [18].

Drugs characterized by rapid onset and rapid elimination of symptoms can also be quickly deactivated. That can be good or bad, depending on the timing of the residue's exchange in the milk and/or meat. Prior to the initiation of treatment, this issue must be studied and highlighted by the veterinarian. Controlled withdrawal plans are prerequisites for avoiding the presence of drug residues in animal origin food products. In this study, products available on the market were presented, where the animal milk was observed to be a lower risk factor of any prohibited contamination and exceeded food safety standards aimed at better, well-balanced nutrition of a population with a higher disposable income level [19].

Plasma concentrations of albumin, lipids, and total proteins decrease during lactation, while those of bilirubin, gamma glutamyl transferase, alkaline phosphatase, lactate dehydrogenase, alanine aminotransferase, and aspartate aminotransferase increase. It has been proven that the transfer of certain drugs, as a result of hormonal stimulation, increases at the beginning of lactation, as in the case of flunixin, for example. Blood drug and residual data concentrations peak upon weaning of the offspring [20].

2.2.1. Biochemical and Hormonal Changes During Lactation

The transfer of drugs and their residues depends mainly on the agent's lipophilicity, distribution in the tissues, dissociation constants, level of protein binding, volume of distribution, metabolism, and elimination half-life. An extreme milk/plasma ratio of a drug suggests that the drug's conduct is influenced mainly by its partitioning. When the blood/plasma ratio is high, the ratio may be due to active transport of the drug. If a low milk/plasma ratio is present, façade removal techniques should be avoided during milk sampling. In this case, if the drug is removed intermammarily, the product may store in the milk somatic cells and may enter the milk stream as a result of the concentration gradient between milk and cells [21].

2.2.2. Pharmacokinetics

Therapeutic concentrations of drugs in milk delivered into the market could be avoided by intravenous, subcutaneous, or intramuscular administration of a drug. Oral administration should be avoided if the drug's residues in internal organs and milk have higher trade restriction limits. The principle of synergy of co-administered drugs should not be used to justify lower dosages of both drugs. It should be emphasized that one of the drugs needs to be registered for administration in lactating animals [22].

2.2.3. Formulation of the Pharmaceutical Preparations

The concentration of a drug or its residues to be transferred in milk is influenced by different factors related to the drug and pharmacokinetic, biochemical, endocrinological, and physiological changes during lactation and gestation of dairy animals [23].

The use of veterinary drugs, in general, involves the treatment of specific pathogens of animal diseases, resulting in veterinary drugs with limited treatment targets and action scopes. These drugs generally have a wide range of specific drug residues in animal-origin food after the drug is metabolized, leading to a public concern regarding drug residues remaining in animal-origin food, which seriously affects consumers' health. It is difficult to detect veterinary drugs' residues in animal-origin food due to the complex composition of these products and differences between drug types and action mechanisms. Sixty percent similarity appears in both the physical and chemical properties of many drug components. The action mechanism of some veterinary drugs is similar, which results in different residues with similar physical and chemical characteristics and similar drug action methods. The complex composition of animal-origin food also yields further interference to the detection of drug residues in animal-origin food. Most years, there is no rapid, convenient, effective, sensitive, or specific method to detect veterinary drug residues in animal-origin food in the initial production period. Few more sensitive methods may be applied only in the follow-up period. Then a rapid, accurate, and reliable technology to detect the amount of veterinary drug residues is still in hot pursuit of the researchers [24, 25].

It is difficult to detect veterinary drugs in animal-origin food due to its complex composition and differences between drug types and action mechanisms. Most years, there is no rapid, convenient, effective, sensitive, or specific method to detect veterinary drug residues in animal-origin food in the initial production period. These detection methods can be divided into two categories: screening and confirming. Screening methods usually use qualitative detection methods to detect veterinary drug residues in animal-origin raw material rapidly and conveniently. Confirming methods use sensitive and accurate measurement methods to confirm the content of veterinary drug residues to help meet the maximum residue limits. The detection methods include the biological method, chemical method, physicochemical method, and biosensors. The compound detecting technology is usually applied in these methods. The compound detecting technology is the most common research trend and developing direction for veterinary drug detection in animal-origin food in recent years, which will help to provide a single ultra-high-precision facility, stable, and reliable detection results with the guidance of laboratory accuracy and labor productivity [26, 27].

3.1. Analytical Techniques

The most widespread technique is the HPLC-MS method, combining a technique allowing the chromatographic separation of substances and an advanced detection method identifying their presence in the sample. The most common methods used for the detection of residues of lincosamides and streptogramin antibiotics, added to the determination of residues of multiple drugs in a drug group, are LC-MS/MS. The most commonly used or recommended methods for each drug mainly involve HPLC-UV, and for some drugs, the LC-MS/MS [27].

In particular, microbiological methods are mostly employed for controlling the spread of drug residues in food commodities, emphasizing the importance of the cost factor, simplicity of analysis, and high capacity of tests [28].

Standard methods for detecting antibiotic residues in food include receptor-binding assays, especially the growth-inhibition test. These assays, however, only cover random groups of antibiotics. Modern analytical methods, such as chromatographic techniques (LC, HPLC, GC, and HPLC and its variants), coupled with a multitude of detection methods (UV, FLD, MWD, MS), are also used frequently [29].

3.2. Regulatory Limits

Maximum residue limits ensure the safety of veterinary medicinal products, prohibiting the presence of residues, other than the allowed lowest concentration, of the medicine in the animal food products resulting from high exposure during animal treatment. While microbial requirements, added sweeteners, or color usage are only translationally regulated, maximum limits for residues of veterinary drugs present in animal food products are established for the entire period in which the antimicrobial action of the drug is effective and are then continuously reassessed for improvement. The reason for the establishment of these types of regulation is well known. In contrast to levies determined for pesticides, for which safety is secured exclusively by market forces, veterinary drug safety for humans in the sense of health protection at the consumer level is of general interest and worsens the animal producer's economic weak position because these regulations must guarantee that all animal farmers could follow recommended withdrawal periods to be compliant with the placing on market requirements. In all countries, compulsory and effective residue surveillance within a well-defined quantitative system drives essential compliance with the mandatory maximum residue limits and residues of prohibited substances and pharmacologically active metabolites. The zero-tolerance concept has been applied over the years to screen barriers of the syndromic surveillance of transmissible diseases and as it is also disease-specific, this solution is appropriate or broadly applied but primarily defined for certain diseases [7, 30].

Evaluating physiological functions and pharmacologic principles of an administered drug to assess the likelihood, rate, and intensity of reactions or damage it may induce on the target organism is fundamental in drug action assessment. The action of a certain drug is manifested at the site where concentrations of this compound exceed a value that was established experimentally. Nevertheless, the administration of a drug involves distribution to many tissues and body fluids, so damage may occur in the site of action or, typically, in other tissues and organs. Regulatory limits are established in order to: (i) control potentially harmful drug action effects; (ii) ensure that meat and milk, and also other animal-derived food products (honey, eggs, or blood), are safe for human consumption [31].

Currently, with the improvement in food safety monitoring standards and the popularization of advanced monitoring instruments, more and more veterinary drug residues have been detected in animal husbandry food. The potential health risks associated with veterinary drug residues have been overlooked to a certain extent. Although the current national MRLs and monitoring targets of veterinary drug residues only reflect public food safety levels, these residues may also have some potential risks. The dependence on the use of veterinary drugs can also lead to the deposit of a vast number of drug residues in animals. When public food safety has been ensured and security risks removed, the negative externalities arising from the use of veterinary drug residues are increasingly receiving public attention. Therefore, in the development of modern and intensive farming, extra caution should be taken for the use of veterinary drugs. Reasonable and safe use of veterinary drugs should be promoted, which will also promote the development of the livestock industry in a green, healthy and sustainable direction [32, 33].

Veterinary drug residues in foods of animal origin may be harmful to consumers. This risk should not be ignored. With the development of farming and livestock industry, the use of veterinary drugs in animal husbandry increases. Although the use of veterinary drugs has effectively protected the production of animal husbandry, they are with some potential harmful side effects. This has also been inviting the attention of consumers. The World Health Organization, the Food and Agriculture Organization of the United Nations, as well as the European Union have formulated strict MRLs and monitoring requirements for veterinary drug residues in foods of animal origin, and established MRL regulations for a large number of veterinary drugs. Research and monitoring of veterinary drug residues in food safety have achieved a lot. These studies give an in-depth understanding of the safety of veterinary drugs in areas such as pharmacokinetics, residues, toxicology, and public health [34, 35].

4.1. Antibiotic Resistance

Knowledge of the prevalence and distribution of antibiotic resistance is essential for the management and proper use of antimicrobial agents in livestock and to reduce the presence of therapeutic residues in products of animal origin. With regard to the study of antimicrobial resistance in microorganisms associated with food, various investigations, more than others, are aimed at the evaluation, in particular, of Salmonella, Escherichia coli, and coagulase-positive staphylococci. The development and spread of antimicrobial resistance are due to various concomitant factors: the continual use of antibiotics used for both human clinical and veterinary reasons, used not only through food of animal origin; the common practice of not concluding full courses of antibiotic treatment (both in animals and in humans); tendencies to use antibiotics without the necessary tools to determine the most suitable treatment. In the presence of multidrug-resistant strains, the use of synergistic antibiotics should be strategically necessary in proportion, with the aim of limiting to the greatest possible extent the resistance, both under the aspect in the perspective of preserving the effectiveness of the drugs active against the bacterial strains themselves, and from the human health perspective. Such precautions would appear certainly significant in relation to human health, but also with respect to the choice of therapeutic treatments in animals, certainly opportune, in the case of foot infections in sheep, in order to avoid the promotion of extensive forms of bacterial resistance, not only directed toward fluoroquinolones, but also toward subgroups of macrolides, tetracyclines, lincosamides, pleuromutilins, phenicols, β-lactams, and with specific reference to the transmission of antibiotic resistance at the microbiota level, inducing a reduction in the benefits of polytherapy treatments, and in general able to involve the entire antimicrobial arsenal. Information and prevention about infectious diseases are direct purposes of good animal health management, and ensuring these conditions the safety of products of animal origin is guaranteed: it is subjected to sections of veterinary health protection, born from well-structured examination procedures and an interdisciplinary approach. Every activity linked to the control of veterinary drugs, such as monitoring, control, and prevention programs intended for animal health, food safety, and health, from a public and private point of view, is part of animal health. In the protection of animal welfare, the need to increase market shares and encourage responsible use, reducing environmental pollution and resistance-generating practices [3, 36, 37].

The indiscriminate and excessive use of antimicrobial agents in therapeutic and subtherapeutic treatments, as well as prophylactic use of chemotherapeutic agents in food-producing animals, is one of the most important factors that favor the emergence and diffusion of resistant bacterial strains. The phenomenon of bacterial resistance represents a growing risk to public health and is determined by the capacity of bacteria to adapt rapidly to the selective pressures imposed on them by the environment. It should be noted that bacterial resistance is of natural origin, as well as the coexistence of resistant and non-resistant strains of the same bacterial species. However, antimicrobial agents act as selective factors, favoring the selection of resistant strains, and creating the danger of transferring them to humans through the food matrix (milk and derivatives, meat in particular) and the environment [38, 39].

4.2. Toxicity and Allergenicity

The reporting of pharmacologically toxic dose information for some classes of xenobiotics is based on testing. However, this is a complex issue as there are numerous variables that influence the subsequent interpretation of toxicological information and dosages. Allergenicity to drugs belongs to a different group of possible side effects and can occur after a first exposure as well as after several treatments. High priorities for inclusion of veterinarians in new liquid chromatography–electrospray ionization–tandem mass spectrometry (LC-ESI-MS/MS) based multiple residue methods should be given to authorized compounds with narrow safety margins [40].

Toxicity is the capacity for producing injury when introduced into a living organism or system. It may cause death or adverse effects, such as growth depression, poor reproductive performance, reduced feed conversion, organ damage or a negative impact on tissue and product quality. Allergenicity is an abnormal allergic condition of the body in response to re-exposure to an allergen that previously resulted in a reaction in the normal immunocompetent individual [41].

There is also misleading information on the use of withdrawal periods provided through word-of-mouth, which may result in drug residues with potential negative effects on public health. It is fundamentally important to first explain and improve awareness of the direct negative effects of drug residues in animal-based food before training the public and farmers about clinical practices and drug withdrawal periods. Awareness is the key in this case. It is necessary to develop knowledge and experiences relating to legal regulations and control procedures for veterinary, nutrition and diet regimes, production management technology, etc. This is also an objective of the Residue Task Force on drug residues and residues in the case of hunting abroad. Reliable services and information on administrative matters are essential to ensure compliance with the rules. In Spain, official surveillance and control are carried out through taste tests and examinations conducted on farmers and industries [1, 42].

Mitigating strategies for minimizing veterinary drug residues in milk and meat include careful veterinary administration and the rational use of veterinary drugs aiming at reducing dosages by accurately determining the concentration of infectious agents. Using targeted drugs and antibiotics in closed systems increases the efficiency and safety of milk and milk products in public health aspects. By extending animal holding time intervals or limiting withholding of the feed after veterinary drug administration, it always provides an effective and resource-saving way of reducing the risk of residues in livestock products. Improving the management of livestock breeding procedures is a measure to minimize antibiotic use and reduce veterinary drug residue risk in livestock products. The Pathogen Reduction; Hazard Analysis and Critical Control Points (PR-HACCP) approach is another useful strategy for risk assessment (e.g., prudent use of veterinary drugs) in milk and milk products [30, 43].

5.1. Good Agricultural Practices

In feed, they can be used in ruminants ionophore coccidiostats (monensin, lasalocid, salinomycin, etc.), which produce no public health problems. As for the use of antibiotics as growth promoters in feed for the small intestinal vegetative bacteria, only zinc oxide can be used. In addition, they use coccidiostats and histomonostats in compound feed. Formulations with 200 g lasalocid sodium/g of the product with 1-2% inclusion in the daily ration provide efficacy in coccidiosis. The daily ration of turkeys, pullets, and laying hens at the beginning of the coccidiosis preventive program will be 1.4-1.5 kg and 1 kg (lasalocid only) and 0.6 kg. In the case, in pullets already fed compound feed before initiation of therapy, when feed vehicles are not used, the first ingestion occurs at the first time after the retraining of hunger for medication, and the second time there is no ingestion of the product [44, 45].

Good agricultural practices (GAP) and good farming practices (GFP) are those sustainable practices that involve the use of phytosanitary products and the correct application of veterinary medicines, in order to reduce the need for use to a minimum and protect humans, animals, and the environment during their application and use. The correct use of both requires that the applicator of the product is duly and continuously trained, the products are duly authorized, properly identified, and prepared and conditioned according to the maximum security conditions and that the direct and indirect environmental impacts are taken into account. The percentage of treatments that are unnecessary in veterinary medicine ranges from 40% to 70% but can be reduced up to 30% by implementing GFP. Of the active substances used, about 24% are prohibited, as is the case of certain antibiotics. The lack of commercialization of some antibiotics, as well as of some commonly used analgesics in small ruminants, has been demonstrated [46, 47].

5.2. Withdrawal Periods

Drug withdrawal periods are the time intervals between the drug administration to animals and the release of their products (milk and meat) to the market, during which the residue levels in animal products must fall below permitted limits for the residue. Maximum accepted residue levels (MRLs) and recommendations on withdrawal periods are set by national food safety agencies or in some cases, there would be a Codex Alimentarius Standard. The set period for a withdrawal time will depend on different factors. This would include the pharmacokinetic property of the drug in question, that is, the absorption, distribution, metabolism, and excretion of the drug within the animal, physiological changes, the different types of chemical structure, route, and regularity of administration and residual localization or persistence of the drug within the edible tissue, physiological and toxicological considerations about tissue residue persistence, the margin of safety, statistical factors such as the number of animals tested, the assay sensitivity, and the biological variability of the residue concentration, and inter alia food safety, environmental, and international trade considerations. Additionally, this would also depend on the required sensitivity of the detection system and analytical techniques being used to determine the marker residues' presence in collected samples [34, 48].

Educating through the media is of utmost importance, as these agents both shape and disclose public opinion in sensitive areas of human concern. The veterinary medical community should use opportunities where they can make useful contributions and where they can, at the same time, benefit from the resulting information feedback. Economic pressures to improve cost-effectiveness are there to remain and to further increase. But they should target the overabundance of drugs and not the (already precarious) consideration of the consumer. The present balance is far from optimal, and the perspective it offers does the credit to anyone dealing professionally with food safety issues. But the scale of these factors is precisely what forces science to broaden the domain of responsibilities and to redefine its objectives. We can, thus, think of them as prods stimulating our disciplines into the ethical and moral direction they have lost sight of during the often undisputed modernization rush [49, 50].

Proper use of veterinary drugs in food-producing animals, including the concept of residue avoidance, should gain attention from all individuals involved in the management and processing of farm products. Both livestock producers and veterinary practitioners need to be suitably educated. Adequate extension and constant provision of guidelines in written form should be part of the overall government strategy applied through state authorities. Unfortunately, although responsible bodies are well aware of the risks of consumer ignorance and false suspicions, so far, consumer awareness and education do not figure prominently as intervention strategies. To have a deep effect, measures to correct that should follow various lines to reach and inform diverse groups, including shoppers, schools, and the lay audiences. But sustained public relations operations and judicious use of advisory practices still have to correct the wrong impression according to which the consumer's watchdog role in food safety is not sufficiently exercised [34, 51].

At present, a growing number of novel veterinary drugs with unmetabolized or pharmacologically active residues have highlighted the utmost importance of the quality and safety of the milk and meat produced by animals. In response to these challenges, the scientific research needs in-depth characterization of the residue levels, deletion times, influencing factors, and residue depletion of the veterinary drugs. Moreover, as a substitute for the ultimate bad effects in human consumers and to avoid the withdrawal period, a wider horizon should consider the development of innovative veterinary drug formulations. Consequently, this comprehensive review could provide vital information for a deep understanding of the impact of veterinary drugs on the quality of milk and meat products from animals.

This paper provides a comprehensive review of the impact of the application of veterinary drugs on the quality of milk and meat in animals. Consequently, the following conclusions and future perspectives can be summarized. Drugs, including antibiotics, growth promoters, hormone-like substances, β-agonists, and anthelmintics, are widely used in the veterinary field. However, the abuse of these drugs has a serious impact on the quality and function of milk and meat. Although the residues of veterinary drugs in animal products have been strictly regulated by the government and the scientific community has implemented many analytical methods for detecting these residues, issues such as a lack of uniform detection methods, undetectable masking, and other tampering phenomena have made it difficult to control the veterinary drug residues to a minimal level.

Funding: No funding sources.

Conflict of interest: None declared.

Ethical approval: The study was approved by the Institutional Ethics Committee of Northern Technical University

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