Veterinary drug residues in meat related edible tissues
Important terms:
 Meat edible related tissues: Meat is defined as those animal tissues which are
suitable for use as food. These are the main soft tissues of the carcass and muscle.
https://www.fao.org/4/t0279e/t0279e06.htm#:~:text=Meat%20is%20defined%20as%20th
ose,45%20percent)%20and%20connective%20tissues.
 Residue is defined: as any compound or metabolite of a compound that is present
in edible tissues from food animals.
https://www.ncbi.nlm.nih.gov/books/NBK232575/#:~:text=Residue%20is%20defined%2
0by%20CVM,result%20of%20the%20compound's%20use.
 Introduction:
Application of veterinary drugs in livestock production is inevitable as they are
essential for treatment of diseases, prevention of diseases, modification of
physiological functions, improvement of growth and productivity.
However, recent reports have revealed that the use of veterinary drugs in large
amounts could result in deposition of antimicrobial residues in muscle and organs of
animal. Consumption of these residues in animal products may pose health risk to
consumers including development of antibiotic resistance bacteria, allergy,
reproductive disorder and hypersensitivity reaction. Here are some common classes of
veterinary drugs that can lead to meat residues:
1. Antibiotics
2. Antiparasitics
3. Hormones and Growth Promoters
4. Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)
5. Sedatives and Tranquilizers
6. Coccidiostats
7. Steroids and Corticosteroids
 How Drug Residues End Up in Meat
The accumulation of residues in meat and organs follows specific biological and
chemical mechanisms that depend on the nature of the substance (drug, pesticide,
heavy metal, etc.) and the metabolic pathways of the animal. The following points are
a detailed explanation of the mechanisms involved:
1. Absorption and Distribution
2. Metabolism and Biotransformation
3. Accumulation in Specific Tissues
5. Excretion and Elimination
6. Bioaccumulation
Key Factors Affecting Accumulation
 Chemical Nature of the Substance: Lipophilic compounds are more likely to
accumulate in fat, whereas hydrophilic substances accumulate in organs like the
liver and kidneys.
 Dosage and Exposure Duration: Higher doses and longer exposure periods lead to
greater accumulation.
 Metabolic Rate of the Animal: Animals with slower metabolic rates may
accumulate residues more easily.
 Age and Health of the Animal: Older or sick animals may have reduced capacity
for detoxification and elimination, leading to higher residue levels.
Maximum Residue Limits (MRLs) are the highest levels of a chemical residue, such as
veterinary drugs or pesticides, legally allowed in food products like meat and organs.
MRLs are established by regulatory bodies such as the Codex Alimentarius
(internationally), the European Food Safety Authority (EFSA) in Europe, and the U.S.
Food and Drug Administration (FDA). Here are examples of MRLs for some common
substances in animal products
1. Veterinary Drug Residues
Drug
Oxytetracycline (antibiotic)
Its amount in the meat products
Beef and Pork Muscle: 200 µg/kg, Liver:
600 µg/kg, Kidney: 1200 µg/kg,
2. Pesticide Residues
Pesticide
DDT (Dichlorodiphenyltrichloroethane,
banned in many countries)
Its amount in the meat products
Beef and Pork Fat: 500 µg/kg
3. Hormone Residues
Hormone
Estradiol (growth hormone, banned in the
EU but used in the US)
Its amount in the meat products
Meat: Varies by region; banned in the EU,
with strict limits in other regions.
4. Heavy Metal Contaminants
Heavy metal
Lead
Its amount in the meat products
Meat (muscle): 100 µg/kg, Liver: 500
µg/kg, Kidney: 1000 µg/kg
The values can vary depending on the regulatory authority, the type of animal, and the
geographical region. Different countries have different standards, and some substances
may be entirely banned in certain regions.To find specific MRLs for a region or product,
you can consult:
 Codex Alimentarius (for international MRLs)
 European Food Safety Authority (EFSA) (for European MRLs)
 U.S. FDA and USDA (for U.S. MRLs)
 Health Risks Associated with Drug Residues
1) Antibiotic resistance
 Development and spread of drug-resistant bacteria, which is a potential risk to
public health.
2) Hypersensitivity reaction
 Hypersensitivity reactions, resulting in allergic symptoms like skin rashes, itching,
hives, breathing difficulties, and even anaphylactic shock
 Sulphonamides may cause allergic reactions in up to 3% of those using these
drugs.
 Penicillin allergic reactions are the most frequent, affecting up to 10% of people .
Anaphylactic reactions were observed after consumption of beef or pork
containing penicillin
3) Disrubtion of normal microflora
 Disrupting intestinal flora, leading to gastrointestinal disorders
.
4) carcinogenic effect
 drug residues have potential to induce cancer by disrupting the normal biological
functions of intracellular components such as DNA, RNA, proteins, glycogen,
phospholipids, and glutathione through covalent bonding.
 Chloramphenicol raises the risk of cancer
5) teratogenic effect
 Tetracycline, is known to pass through the placental membrane and accumulate in
the developing embryo’s bones and teeth.
6) Hormonal disturbances
The hormone residues in meat results into adverse effect on human health as it mimic hormone
functions and are known for their interference on the function of the endocrine system cause
endocrine disturbance such as disrupt in human hormone balance, causing developmental
problems, interfering with the reproductive system and can even lead to the development of
breast, prostate cancer
 Testing Methods for Veterinary Drug Residues
1. Chromatography-Based Methods:
• Liquid Chromatography-Mass Spectrometry (LC-MS): It’s highly sensitive and
specific, especially for complex drug matrices.
• Gas Chromatography-Mass Spectrometry (GC-MS): Utilizes gas
chromatography with mass spectrometry, making it highly specific for volatile or
semi-volatile residues.
• High-Performance Liquid Chromatography (HPLC): used widely for its
specificity in detecting different drug classes.
2. Immunoassay-Based Methods:
• Enzyme-Linked Immunosorbent Assay (ELISA): Uses antibodies to target
specific drug residues, providing high specificity, particularly for antibiotics and
hormones.
• Radioimmunoassay (RIA): Similar to ELISA but uses radiolabeled antibodies
3. Mass Spectrometry with Laser Desorption:
• Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry (MALDI-MS):
Uses laser desorption for ionizing large molecules, allowing highly specific
detection of drug-protein conjugates or complex residues.
4. Microbial Inhibition Tests: Uses bacterial cultures to detect antibiotic residues
by observing growth inhibition zones.
5.Biosensor-Based Methods: Utilizes biological components like enzymes or
antibodies to detect drug residues in a rapid manner.
https://asean.org/wp-content/uploads/2021/12/FAFD-44.-ASEAN-Guideline-drugresidue-detection.pdf
 How to reduce drugs residues in meat
1. Proper Withdrawal Periods: Ensure that animals are given enough time to metab
olize and eliminate the drugs before they are slaughtered. This is known as the wit
hdrawal period, and it varies depending on the drug used.
2. Accurate Treatment Records: Keep detailed records of all medications administ
ered to animals, including dosage, frequency, and withdrawal periods. This helps i
n ensuring compliance with regulations.
3. Consultation with Veterinarians: Work closely with veterinarians to determine t
he appropriate use of veterinary drugs and to establish accurate withdrawal times.
4. Adherence to Injection Site Limitations: Follow guidelines for injection sites to
prevent tissue damage and ensure proper drug absorption.
5. Hygiene and Disease Prevention: Implement strict hygiene standards and prevent
ive measures to reduce the need for antibiotics and other drugs. This includes vacc
ination, proper nutrition, and biosecurity measures.
6. Alternative Treatments: Consider using plantderived antimicrobial substances and probiotics as alternatives to traditional antibi
otics1.
7. Cooking Methods: Some cooking methods, such as boiling, roasting, and grilling,
can help reduce drug residues in meat after slaughter.
Some experimental researches discovered that
Thermal treatments: oxytetracycline, ampicillin, and chloramphenicol residues were
decreased by 12%-50%, sulfonamide residues by 45%-61%, and antihelmintic
residues by 11%-96%.
Pressure cooking: aldrin, dieldrin, and endosulfan were reduced by 79%-94%.
Fermentation treatments: DDT was reduced by 10% and lindane by 18%.
References:
| A selection of results from model runs to investigate the impacts of... | download table.
(n.d.). https://www.researchgate.net/figure/A-selection-of-results-from-model-runs-toAntibiotic
Compound
Processing method
For
Ampicillin
Grilling/roasting
Meat
Boiling/roasting/microwave
Meat
Boiling/frying
Meat
Boiling/microwave
Meat
Tetracycline Tetracycline/oxytetracycline/doxycycline/chlortetracycline
Ivermectin
Amphenicol Chloramphenicol/florfenicol/thiamphenicol
investigate-the-impacts-of-different-input_tbl4_47791621
Rana, M. S., Lee, S. Y., Kang, H. J., & Hur, S. J. (2019, October). Reducing veterinary
drug residues in animal products: A Review. Food science of animal resources.
https://pmc.ncbi.nlm.nih.gov/articles/PMC6837901/
https://ifrj.upm.edu.my/25%20(01)%202018/(1).pdf
https://www.sciencedirect.com/science/article/abs/pii/S0278691523005744#:~:text=Alth
ough%20the%20natural%20presence%20of,various%20levels%20of%20the%20residues
%2C
https://www.mdpi.com/23048158/13/11/1629#:~:text=37%2F2010%20%5B6%5D.,7%2C8%2C9%5D