IMPORTANCE OF DRUG WITHDRAWAL PERIODS FOR MEAT & MILK-A PUBLIC HEALTH CONCERN
Compiled & Edited by-DR RAJESH KUMAR SINGH, JAMSHEDPUR, 9431309542
Introduction
To safeguard the health and welfare of our farmed animals, veterinary medicines are used as part of a herd or flock health plan. Authorized veterinary medicines used in farmed animals are subject to strict regulatory controls in Europeans countries & US but sorry to say that in our India in spite of regulation related to ethical use of antibiotics on farm animals , no attentions are given on this issue.Now it has become a prime duty of vets to take care of ethical antibiotic/drug uses and make the things aware before livestock farmers about importance of drug withdrawal period, food safety & public health concern.An important consideration is observing a legally defined period of time after the last administration of medicine has been given, before allowing the animal or its produce to enter the food chain (the withdrawal period). these practices provide an assurance that food from animals is safe with regards residues of veterinary medicines.
WHAT IS THE WITHDRAWAL PERIOD?
When a person or an animal is given an antibiotic, it goes to work in the body. The antibiotic does its job killing bacteria, and the body does its job breaking down the antibiotic. This break down takes different times for different antibiotics. It also takes different times in different animals (cows compared to pigs, for example). Some antibiotics have different break down times for different tissues (milk, meat, or liver for example).
The time it takes the body to break down the antibiotic until it is no longer functional or present is called the withdrawal time (or withdrawal period). Once the withdrawal period has passed the antibiotic has been eliminated from the animal’s system.
Every antibiotic has a withdrawal period. Some withdrawal periods are very short, 1 or 2 days. Some are longer, 7-10 days. Some are even longer, up to weeks.
The withdrawal period must be determined for every species of animal the antibiotic can be used on. If the antibiotic can be used in a lactating (milking) animal, the withdrawal period must be determined for both meat and milk. (The withdrawal period for milk is usually shorter than the withdrawal period for meat.) All this testing must be completed before the antibiotic is available for sale
Maximum Residue Limits (MRLs) and Withdrawal Periods
Residues of pharmacologically active substances are described as active substances, excipients or degradation products and their metabolites, which remain in foodstuffs obtained from animals that have been treated with a veterinary medicinal product
The withdrawal period is a specific set period of time, after the last dose of the veterinary medicine has been administered, that must elapse before an animal or foodstuffs from an animal can enter the food chain. To determine the withdrawal period, regulatory authorities must employ a scientific process that includes establishing the Maximum Residue Limit (MRL) for that medicine
The MRL is the maximum concentration of residue accepted by the European Union (EU) in a food product (e.g. meat, milk, eggs) obtained from an animal that has received a veterinary medicine
In the process of establishing an MRL, firstly a No Observed (Adverse) Effect Level (NO(A)EL) is identified through scientific studies with the active substance. The NO(A)EL is the highest dose that does not cause adverse effects. This figure is then divided by an ‘uncertainty’ or ‘safety factor’ e.g. by 100-1000 to determine the Acceptable Daily Intake (ADI). The ADI is the amount of the residue that is considered safe for an individual to eat every day for their lifetime taking into account a number of safety factors. The MRLs are such that consumers can ingest generous amounts of animal foodstuffs every day without exceeding the ADI. A number of factors are taken into consideration here including the amounts of each food eaten per day and how the substance is metabolised and distributed in the various tissues. A MRL is then set for each edible tissue and product to ensure the ADI is not exceeded.
The assessment of the safety of the pharmacologically active substances and their residues occurs before a veterinary medicine intended for food producing animals is authorised for use in the EU
When an MRL has been determined for a veterinary medicine, the withdrawal period is then calculated by taking into account the rate of residue depletion, to below the MRL, in all edible tissues and products
The use of animal medicines is strictly controlled by Indian law, and requires observance of the withdrawal period, which must have elapsed before an animal or its products can be used for human consumption. The withdrawal periods have been calculated using rigorous scientific processes so that veterinary medicines can be authorised and administered to food producing animals, whist at the same time consumer safety is protected.
Every medicine that is given to animals, including antibiotics, has a withdrawal period. Farmers must follow these withdrawal times to be sure no antibiotics are in our food
WHY DOES THE WITHDRAWAL PERIOD MATTER?
These are two very important ways that farmers contribute to food safety every single day. First, by monitoring which medications they give to their animals, how much they give, and when they give it. Second, by maintaining accurate records and sticking to the withdrawal period. There are layers of monitoring in place to make sure that farmers are doing their due diligence and taking care of their animals, their families, and your families.
It simply takes time for the body to break antibiotics (or any medication) down to a form where the medicines are no longer functional and leave the body. This is why withdrawal periods are so important. Following withdrawal periods means that we know there are no traces of antibiotics in the meat or milk you buy at the grocery store. It means that we know that you and your families are not exposed to “extra” or unnecessary antibiotics. It means that farmers are doing everything they can to prevent the development of antibiotic resistance.
Withdrawal period refers to the minimum period of time from administering the last dose of medication and the production of meat or other animal-derived products for food.
The withdrawal period is different for each veterinary medicinal product, animal species and food type, meaning there are different withdrawal periods for meat (slaughter), fish, eggs, milk and honey.
For example, if mastitis is treated with a medicine that requires a withdrawal period of 6 days for milk, the treated cow’s milk may be produced for delivery to a dairy on the 7th day after the last dose, at the earliest.
The purpose of the withdrawal periods is to ensure that foods do not contain residues of pharmacologically active substances in excess of the maximum residue limit (MRL).
To determine withdrawal periods, data on the drug metabolism in the animal is studied. The results of residue studies on a veterinary medicinal product are then compared with the MRL. The withdrawal period is set so that it is long enough to ensure that medicinal residues in the animal’s tissues are below the maximum limit.
Drugs-and-their-withdrawal-periods
While establishing withdrawal periods for antibiotics, a very large margin of safety is used to ensure that even if the withdrawal period is not strictly adhered to, the consumer will not be at risk. In many countries like US, Canada and countries in the European Union, there are strict laws and strategies in place that make sure that farmers obey withdrawal periods. Samples of animal products are taken from farms, shops, border, slaughter houses etc and tested to make sure that residues are not above the maximum allowable limit and that prohibited or illegal antibiotics are not used. If there is violation, investigation is carried out and if appropriate, offenders are prosecuted.
In India, laws may exist about antibiotic withdrawal period but steps are not usually taken to enforce them. As a result many farmers don’t observe withdrawal periods. Antibiotic and pesticide residues are among the reasons why such countries are denied access into American and Europe livestock market.
How Antibiotic Withdrawal Period Affects Your Health
Antibiotic residues can lead to allergy, cancer, antibiotic resistance and other health effects. Residual penicillin in animal products can cause allergic reaction in some people. Other antibiotic residues like tetracycline, sulphonamides and aminoglycosides can also cause allergic reactions.
One of the most important concerns is antibiotic resistance. Animal products containing antibiotic residues can cause antibiotic resistance in man. The resistant bacteria can then cause diseases in man and such diseases are difficult and expensive to treat. The bacteria may also transfer the resistance to other human pathogens (disease-causing organism).
Cost of Adhering to Withdrawal Periods
Obeying drug withdrawal periods can be financially costly for the farmer. Now imagine your egg layers or cows get sick and you have no other option than to give them an antibiotic with a 7 days withdrawal period. This means that all the eggs or milk produced throughout these 7 days will be thrown away. This is why many farmers in developing countries find it difficult to obey withdrawal periods.
The cost resulting from obeying withdrawal periods can be minimized by following good management practices. This entails following production techniques that help to maximize efficiency and eliminate or reduce infections. It includes proper housing, putting farm biosecurity measures in place, good nutrition, proper vaccination, employing the service of a qualified vet etc.
Herbs and probiotics can help prevent diseases in animals. Various researches on herbs and plant extracts show that they can be use to prevent and treat diseases in animals. With herbs and probiotics, there are no withdrawal periods unlike antibiotics.
Conclusion
Despite the cost associated with obeying antibiotic withdrawal period, it is still necessary that farmers adhere to it. If not it can jeopardize the health of a lot of consumers. The best way to avoid the cost is by following best management practices that will prevent or minimize infections. Using herbs and probiotics as alternatives to antibiotics will also help.We vets can play a vital role by making the livestock farmers aware about the importance of withdrawal period .In India drugs rules and regulations are controlled by centeral drugs standard control organization(CDSCO). There is need of enforcing strict regulation regarding withdrawal period on farm animals by CDSCO.
Reference-On request
