Antibiotic Residues in Milk
Milk is a nutrient-rich biological fluid, naturally designed to support growth and development. It contains:
- Proteins (casein, whey)
- Fats
- Lactose (milk sugar)
- Vitamins and minerals (e.g., calcium, B12)
- Water (approx. 87%)
Due to its complex composition and sensitive biological nature, milk can easily absorb chemical contaminants, including residues of veterinary antibiotics used in dairy animals.
Comprehensive laboratory testing is essential to confirm the absence of these residues, ensuring milk is safe, compliant, and suitable for consumption.
What Are Antibiotics?
Antibiotics are drugs used to treat bacterial infections in animals and humans. In dairy farming, they are commonly administered to:
- Treat mastitis and other infections
- Prevent disease in high-risk conditions
- Promote growth (in some countries, though now restricted)
While these drugs are essential for animal welfare, their misuse or overuse can result in antibiotic residues leaking into milk, especially if proper withdrawal periods are not observed.
Why Do Antibiotics Enter Milk?
|
Source |
Explanation |
|
Direct Treatment of Cows |
Milk collected from animals undergoing antibiotic treatment or shortly after |
|
Non-Adherence to Withdrawal Periods |
Insufficient waiting time before milking leads to residue presence |
|
Cross-Contamination |
Improper cleaning of milking equipment or storage tanks |
|
Feed Contamination |
Antibiotic residues present in animal feed |
|
Environmental Exposure |
Manure runoff, soil leaching, or water contamination affecting livestock indirectly |
Types of Antibiotics Commonly Detected in Milk
|
Class |
Examples |
Use |
|
Beta-lactams |
Penicillin, Amoxicillin |
Mastitis treatment |
|
Tetracyclines |
Oxytetracycline, Doxycycline |
Broad-spectrum bacterial infections |
|
Sulfonamides |
Sulfamethazine |
Bacterial infections and parasites |
|
Macrolides |
Erythromycin, Tylosin |
Respiratory and skin infections |
|
Aminoglycosides |
Streptomycin, Gentamicin |
Severe infections |
|
Fluoroquinolones |
Enrofloxacin, Ciprofloxacin |
Advanced or resistant bacterial strains |
Implications of Antibiotics in Milk
Health Effects on Humans
- Antibiotic resistance: A global health crisis; consumption of residues can promote resistant bacterial strains.
- Allergic reactions: Even small amounts can trigger severe allergies in sensitive individuals.
- Gut microbiome imbalance: Disruption of beneficial intestinal flora.
- Toxic effects: Long-term consumption linked to liver and kidney toxicity.
Environmental Impact
- Manure runoff containing antibiotics can enter soil and water.
- Promotes resistance in environmental bacteria.
- Affects aquatic ecosystems and microbial diversity.
Industrial and Dairy Farms Concern
Antibiotic residues in milk are a growing concern for both industrial dairy processors and primary dairy farms. The presence of these residues is not only a regulatory non-compliance issue but also a public health and economic challenge.
Key Concerns Faced by the Sector:
|
Concern Area |
Details |
|
Regulatory Pressure |
Stricter regulations from FSSAI and export markets mandate zero or minimal antibiotic residues. |
|
Consumer Expectations |
Increasing demand for “residue-free” and “organic” milk places pressure on farms to adopt cleaner practices. |
|
Export Rejections |
Global markets (e.g., EU, US) have strict MRLs; antibiotic traces can lead to shipment bans or returns. |
|
Loss of Certifications |
Non-compliance can result in suspension or cancellation of organic, “antibiotic-free,” or clean-label certifications. |
|
Risk of AMR (Antimicrobial Resistance) |
Overuse of antibiotics on farms contributes to AMR, which is a major global health threat. |
|
Milk Spoilage & Processing Impact |
Residues interfere with fermentation (e.g., in cheese or yogurt), causing batch failures or quality loss. |
|
Reputational Damage |
Media reports or consumer complaints about antibiotic residues can severely harm brand image and trust. |
Why Is Antibiotic Residue Testing in Milk Necessary?
Testing milk for antibiotic residues is not just a regulatory formality, but a critical food safety and public health measure. It ensures the integrity of the dairy supply chain and protects consumers, the environment, and the dairy industry from long-term harm.
Importance of Testing – A Comprehensive View
|
Purpose |
Why It Matters |
|
Food Safety & Public Health |
Ensures that milk is free from harmful antibiotic residues that could trigger allergies or toxicity. |
|
Consumer Protection |
Builds consumer trust by guaranteeing that dairy products are safe and responsibly sourced. |
|
Regulatory Compliance |
Required by national (FSSAI) and international (EU, Codex, US FDA) food safety regulations. |
|
Prevention of Antimicrobial Resistance |
Detects and prevents low-level antibiotic exposure that contributes to the development of AMR. |
|
Export Certification & Trade Readiness |
Export shipments with residue violations face rejection, delays, and economic losses. |
|
Brand Integrity & Market Reputation |
Protects brand image from damage due to product recalls, media scrutiny, or public backlash. |
|
Support for Dairy Farmers |
Helps farmers monitor withdrawal periods and adopt good veterinary practices to avoid contamination. |
|
Environmental Responsibility |
Prevents unchecked antibiotic discharge through contaminated milk, reducing environmental burden. |
|
Quality Assurance & Product Labeling |
Validates “antibiotic-free” or “organic” claims on milk and dairy labels. |
|
Legal Risk Mitigation |
Avoids penalties, license suspensions, or litigation related to non-compliant dairy products. |
Key Parameters to Test
|
Parameter |
Purpose |
|
Antibiotic Residue Levels |
Quantify individual antibiotics or total residues |
|
Maximum Residue Limits (MRLs) |
Check compliance with FSSAI/EU/US FDA limits |
|
Withdrawal Compliance |
Verify if milk complies post-treatment waiting time |
|
Class-wise Screening |
Detect different antibiotic categories |
|
Confirmatory Testing |
Used when screening gives a positive result |
Common Testing Methods for Antibiotics in Milk
|
Method |
Description |
Use Case |
|
Microbial Inhibition Assay (MIA) |
Based on growth inhibition of bacteria in the presence of antibiotics |
Quick screening, cost-effective |
|
ELISA (Enzyme-Linked Immunosorbent Assay) |
Detects specific antibiotics using antibody-antigen interaction |
High-throughput screening |
|
LC-MS/MS (Liquid Chromatography–Mass Spectrometry) |
Highly sensitive, identifies and quantifies multiple antibiotic classes in one run |
Confirmatory and regulatory compliance testing |
|
HPLC (High-Performance Liquid Chromatography) |
Separates and quantifies residues |
Suitable for specific antibiotics |
|
Biochip or Rapid Test Kits |
Portable strip-based or chip-based detection tools |
Field-level, preliminary testing |
Regulations and standards
FSSAI
In October 2024, the Food Safety and Standards Authority of India (FSSAI) notified the First Amendment to the Food Safety and Standards (Contaminants, Toxins and Residues) Regulations, 2024.
This amendment will come into effect from April 1, 2025.
What Does the Amendment Cover?
The amendment focuses on:
- Crop contaminants and natural toxins
- Antimicrobials and veterinary drugs used in animals raised for food
Ban on Use of Antibiotics in Food Animal Production
A major change in the regulation is the complete ban on the use of certain antibiotics at any stage of production in:
- Milk and milk products
- Meat and meat products
- Poultry and eggs
- Aquaculture and its products
This is a stricter approach than earlier rules, which only prohibited antibiotics during processing. Now, even their use during rearing or treatment is not allowed.
Prohibited Antibiotic Classes & Substances
The following have been banned in food-producing animals:
Antibiotic Classes
- Glycopeptides
- Nitrofurans
- Nitroimidazoles
Specific Antibiotics
- Carbadox
- Chloramphenicol
- Colistin
- Streptomycin (and its metabolite dihydrostreptomycin)
- Sulphamethoxazole
Updated List of Antibiotics with Tolerance Limits
FSSAI has also revised the list of allowed antibiotics with maximum residue limits (MRLs).
6 New Antibiotics Added:
- Amoxicillin
- Cephalexin
- Gentamicin
- Penicillin G / Benzylpenicillin
- Sulfamethazine
- Sulfadimethoxine
This brings the total number of regulated antibiotics to 27.
Antibiotics and Their Status in FSSAI Regulations (2018 vs. 2024)
|
Category |
Antibiotics – FSSAI 2018 Regulation |
Antibiotics – FSSAI 2024 Regulation |
|
Highest Priority Critically Important Antimicrobials (HPCIA) |
Ceftiofur, Danofloxacin, Flumequine |
Retained |
|
Cefquinome Sulphate, Colistin, Enrofloxacin |
Not mentioned in new amendment |
|
|
Critically Important Antimicrobials (CIA) |
Apramycin, Erythromycin, Neomycin, Tylosin |
Retained |
|
Dihydrostreptomycin/Streptomycin, Tilmicosin, Tyvalosin Tartrate |
Not mentioned in new amendment |
|
|
— |
Gentamicin (Newly added) |
|
|
Highly Important Antimicrobials (HIA) |
Ampicillin, Cephacetrile, Cephapirin, Chlortetracycline or Oxytetracycline or Tetracycline, Cloxacillin, Lincomycin, Sulfadiazine, Sulfadimidine, Sulfanilamide, Sulphaquinoxaline, Trimethoprim, Virginiamycin |
Retained |
|
Sulfaguanidine, Sulphathiazole Sodium |
Not mentioned in new amendment |
|
|
— |
Amoxicillin, Cephalexin, Penicillin G/Benzylpenicillin, Sulfamethazine, Sulfadimethoxine (Newly added) |
|
|
Important Antimicrobials (IA) |
Spectinomycin, Zinc Bacitracin |
Retained |
|
Tiamulin Hydrogen Fumarate |
Not mentioned in new amendment |
|
|
Not Medically Important for Humans |
Flavophospholipol (Flavomycin) |
Not mentioned in new amendment |
Antibiotics Prohibited in Food Animals: FSSAI Regulations
Below is the table detailing antibiotics prohibited in various food animal sectors before and after the FSSAI's Food Safety and Standards (Contaminants, Toxins and Residues) First Amendment Regulations, 2024.
|
Sector and details |
Before |
Sector and details |
After |
|
Food producing animals, poultry, aqua farming and animal feed supplements (prohibited for manufacture, sale and distribution w.e.f. July, 2019) Agriculture (draft order in which prohibited for import, manufacture or formulation w.e.f. February 1, 2022; complete ban w.e.f. January 1, 2024) Aquaculture: (prohibited for use in coastal aquaculture and in coastal aquaculture inlets including seed, w.e.f. 2005), notified in 2024, in supersession of 2005 guidelines with same set of antibiotics prohibited |
Antibiotics prohibited |
Dairy, poultry and aquaculture production: all animal-derived foods including meat and meat products, milk and milk products, poultry and eggs, aquaculture and its products (w.e.f. April 1, 2025) |
Antibiotics prohibited for use in production |
Note: The table reflects the changes implemented under the FSSAI's Food Safety and Standards (Contaminants, Toxins and Residues) First Amendment Regulations, 2024, effective from the dates specified.
https://fssai.gov.in/upload/notifications/2024/10/67178d79690b3antibiotic%20gazette.pdf
European union
|
Regulation Number |
Title/Scope |
|
(EU) No 37/2010 |
Maximum residue limits for veterinary drugs in food of animal origin |
|
(EC) No 853/2004 |
Hygiene rules for food of animal origin, including milk |
|
(EU) 2019/6 |
Veterinary medicinal products, use and restrictions |
|
(EC) No 2073/2005 |
Microbiological criteria for foodstuffs |
https://www.sciencedirect.com/science/article/pii/S0928098723001033
Eurofins' Role in Testing Antibiotic Residues in Milk
Eurofins Analytical Services India Pvt. Ltd., part of the global Eurofins Scientific Group, plays a critical role in ensuring the safety, quality, and regulatory compliance of milk and dairy products by offering comprehensive antibiotic residue testing.
Eurofins Testing Capabilities for Antibiotics in Milk
|
Service |
Details |
|
Target Compounds |
Beta-lactams, sulfonamides, aminoglycosides, tetracyclines, macrolides, quinolones, chloramphenicol, and others |
|
Matrices Tested |
Raw milk, pasteurized milk, UHT milk, flavored milk, and other dairy products |
|
Testing Technologies |
LC-MS/MS, HPLC, Microbial Inhibition Assays, ELISA |
|
LOD/LOQ Sensitivity |
As per FSSAI, Codex, EU, and US FDA MRL requirements |
|
Rapid Screening Tools |
Qualitative detection through validated field and lab-based ELISA kits |
|
Confirmatory Analysis |
Quantitative confirmatory methods using LC-MS/MS as per regulatory guidelines |
|
Turnaround Time |
Fast-track services available for urgent release and export requirements |
Accreditations & Compliance Support
Eurofins' labs are:
- NABL (ISO/IEC 17025) accredited
- Recognized under FSSAI, LAAF (US FDA), and ILAC
- Equipped to test as per FSSAI 2024 First Amendment Regulations for veterinary drugs
Applications Across the Dairy Value Chain
Eurofins services benefit:
- Dairy farms & cooperatives: Routine surveillance of milk supplies
- Milk processors: Batch release testing and quality assurance
- Exporters: Compliance with EU, US, and Codex MRLs
- Organic & antibiotic-free brands: Verification of marketing claims
Why Choose Eurofins?
|
Feature |
Benefit |
|
Global network of 900+ labs |
Standardized methods and international reach |
|
Advanced detection technologies |
Accurate, low-level residue analysis |
|
Regulatory expertise |
Support in FSSAI, Codex, EU, and US FDA compliance |
|
Custom test packages |
Tailored testing for bulk milk, ingredients, or products |
|
Digital reporting |
Secure, export-ready certificates and test reports |
