DETECTION AND MONITORING OF ARS

The detection and monitoring of ARs in foods are essential for safeguarding public health, ensuring regulatory compliance, and maintaining the technological integrity of food-processing systems [31]. Antibiotics used in animal production frequently persist in food matrixes such as milk, meat, and fish, necessitating reliable analytical approaches for their identification and quantification [12]. Beyond simple detection, effective monitoring systems must integrate analytical performance, sampling strategies, validation protocols, and surveillance capacity, particularly across diverse regulatory and economic settings [11]. Accurate detection and quantification of ARs in food products require the use of reliable analytical techniques with varying levels of sensitivity, specificity, cost, and operational complexity. Table 3 presents a comparative analysis of the major analytical methods currently employed for the detection of ARs in foods, highlighting their principles, target compounds, analytical performance, practical advantages and limitations, as well as their suitability for implementation in low- and middle-income countries [6, 11, 12, 19, 21, 31, 48].

Chromatographic methods

Analytical techniques such as LC-MS and gas chromatography–mass spectrometry remain the gold standard for AR detection because of their high sensitivity, specificity, and ability to detect multiple residues simultaneously [19]. These methods enable quantification of antibiotics at concentrations well below MRLs, making them indispensable for regulatory compliance [11]. Liquid chromatography–mass spectrometry, in particular, has demonstrated excellent performance in complex matrixes such as milk, meat, and seafood [12].

Despite their analytical robustness, these techniques are associated with high operational costs, require skilled personnel, and entail labor-intensive sample preparation, which limit their widespread application in resource-constrained environments.

Immunological and rapid screening methods

ELISA is widely used for large-scale screening because of its simplicity, cost-effectiveness, and relatively rapid turnaround time [31]. These assays have been successfully applied to detect tetracyclines and chloramphenicol in dairy and aquaculture products [6]. In addition to ELISA, rapid screening tools such as lateral flow assays and dipstick tests have emerged as practical solutions for on-farm and in-plant monitoring, enabling early detection of contamination before processing.

However, these methods generally exhibit lower sensitivity and specificity than chromatographic techniques and therefore require confirmatory testing [12]. Nevertheless, their affordability and portability make them particularly attractive for routine screening applications.

Microbiological assays and low-resource approaches

Microbiological assays remain relevant, particularly in low- and middle-income countries, because of their affordability and ease of use [48]. These methods detect ARs by inhibiting the growth of sensitive bacterial strains [31]. However, their inability to identify specific antibiotic compounds, quantify residue concentrations, or distinguish among residue classes limits their reliability for regulatory purposes. Consequently, microbiological assays are better suited for preliminary screening than for definitive analytical confirmation [6].

Advanced and emerging technologies

Recent technological developments have expanded the analytical landscape for AR detection. High-resolution mass spectrometry (HRMS) provides enhanced accuracy and enables the detection of a broad spectrum of compounds, including emerging contaminants [19]. Biosensors represent another promising innovation, utilizing biological recognition elements such as enzymes and antibodies to provide rapid, real-time detection of specific antibiotics [21].

These systems have been applied successfully for detecting β-lactams and sulfonamides in milk and meat, offering practical solutions for industrial monitoring [12]. Furthermore, the integration of nanotechnology into biosensor platforms has significantly improved sensitivity, enabling the detection of residues at ultra-low concentrations. Nevertheless, challenges related to standardization, validation, and large-scale implementation remain unresolved [19].

Analytical challenges and validation constraints

Despite considerable technological progress, several analytical challenges persist. Detection methods must account for matrix effects, whereby food components interfere with analytical signals and potentially affect accuracy and reproducibility [11]. Validation parameters such as limit of detection, limit of quantification, recovery rates, and precision are critical for ensuring method reliability. However, these parameters are not consistently standardized across laboratories and regions, thereby limiting the comparability of results.

Sampling strategies also represent a major constraint. Variations in sampling frequency, sample size, and representativeness may result in underestimation or overestimation of residue prevalence, particularly in heterogeneous food systems. Consequently, harmonization of validation procedures and sampling protocols remains an important priority.

Surveillance and regulatory monitoring

Surveillance systems play a central role in ensuring food safety and regulatory compliance. In regions such as the European Union and the United States, structured monitoring programs based on routine sampling and testing have proven effective in identifying contaminated products and enforcing compliance with MRLs [12].

Method | Principle | Target compounds | Sensitivity (LOD) | Specificity | Cost | Turnaround time | Advantages | Limitations | Suitability for low- and middle-income countries | References
LC-MS/MS | Chromatographic separation coupled with mass spectrometric detection | Multi-class antibiotics (β-lactams, tetracyclines, sulfonamides, quinolones) | Very low (ng/kg) | Very high | Very high | Long | Highly sensitive; multi-residue detection; high quantitative accuracy | Expensive; complex sample preparation; requires skilled personnel | Low | [11, 12, 19]
GC-MS | Gas-phase separation with mass detection following derivatization | Volatile or derivatized antibiotics | Low (µg/kg) | High | High | Long | High analytical precision; well established method | Requires derivatization; limited applicability | Low | [19]
HRMS | High-resolution mass spectrometry for exact mass detection | Broad spectrum compounds, including unknown and emerging residues | Ultra-low (ng/kg) | Very high | Very high | Long | Detects emerging contaminants with high accuracy | Very expensive; complex data analysis | Very low | [12, 19]
ELISA | Antibody-antigen interaction | Specific antibiotic classes (tetracyclines, chloramphenicol, β-lactams) | Moderate (µg/kg) | Moderate–High | Low–Moderate | Short | Rapid, cost-effective, and suitable for large-scale screening | Cross-reactivity; requires confirmatory testing | High | [6, 31]
Lateral flow and dipstick tests | Immunochromatographic detection | Target-specific antibiotics | Moderate | Moderate | Low | Very short | Rapid, portable, and suitable for field applications | Lower sensitivity; qualitative or semiquantitative | Very high | [11, 12]
Microbiological assays | Growth inhibition of sensitive bacteria | Broad spectrum antibiotics | Low–Moderate | Low | Very low | Moderate | Simple, inexpensive, and requiring minimal equipment | Nonspecific; no quantification; false positives | Very high | [31, 48]
Biosensors (including nanobiosensors) | Biological recognition coupled with signal transduction | Specific antibiotics | Low to very low | High | Moderate | Very short | Real-time detection; portability; high sensitivity | Limited standardization; emerging technology | Moderate | [19, 21]
High-performance liquid chromatography without mass spectrometry | Liquid chromatographic separation | Selected antibiotic classes | Moderate | Moderate | Moderate | Moderate | Widely available and reliable | Lower sensitivity than LC-MS; limited multi-residue detection | Moderate | [12]

However, in many low- and middle-income countries, surveillance systems remain fragmented because of limited infrastructure, inadequate funding, and insufficient technical expertise [6, 48]. This disparity contributes to higher prevalence rates of AR contamination and highlights the need for scalable and cost-effective monitoring solutions.

Regulatory disparities and global challenges

Inconsistent regulatory frameworks further complicate AR monitoring. MRLs vary considerably among regions, leading to differences in safety standards [4, 11]. These inconsistencies create barriers to international trade and hinder the global harmonization of food safety practices. Products considered compliant in one jurisdiction may be rejected in another, emphasizing the importance of coordinated regulatory approaches.

International organizations such as the Codex Alimentarius Commission and the World Health Organization (WHO) have established guidelines to support harmonized monitoring systems [1, 4]. Nevertheless, the effectiveness of these frameworks ultimately depends on their implementation at the national level, which remains uneven across different regions.

Critical synthesis

Overall, the detection and monitoring of ARs involve balancing analytical performance, cost, and feasibility. Although advanced techniques such as LC-MS and HRMS provide exceptional accuracy, their accessibility remains limited, particularly in resource-constrained settings. Conversely, rapid screening methods offer scalability and affordability but require confirmatory analyses to ensure reliability.

These considerations highlight the need for integrated monitoring systems that combine complementary analytical approaches. Future efforts should focus on improving the affordability of advanced technologies, harmonizing validation protocols, strengthening sampling strategies, and developing context-specific solutions suitable for both industrial and smallholder production systems.