Pakistan stands at fourth position in milk producing countries. According to Pakistan Dairy Association, Pakistan has 5 million milk producing animals which produce 46,000 liter milk per annum and contribute 11.7% to total GDP. Milk contain 8.7% water, 4.9% carbohydrate in the form of lactose, 3.4% Fat, 3.3% Protein and different Vitamins like vitamin A, B1, B2, B3, B5, B6, B12, C, D, E, K and folate which contributes as cofactor in metabolism, antioxidant and oxygen transportation. Milk also contains important minerals including calcium, copper, iron, magnesium, manganese, phosphorus, potassium, selenium, sodium and zinc. Milk provides 3% energy in Asia and Africa as compared to 8-9 % in Europe and 6 to 7% dietary protein in the former regions as compared to 19% in Europe.
Apart from these benefits of milk, there are some corners where milk can play crucial role in damaging human health in different ways. The hazardous effects of milk are mainly due to presence of antibiotic residues in milk. Antibiotics are most commonly used for therapeutic purpose in dairy cows in case of mastitis. These antibiotics are released in milk of treated animals and consumption of milk from these animals is undesirable for a number of reasons. Antibiotic residues in milk can cause allergenic or toxicological effects on consumers, selective pressure for antibiotic resistant strains, and eventually technological problems in the production of fermented foods. A study conducted in Pakistan during 2006 revealed that the beta lactam group of antibiotics is responsible for more than 50% of all milk antibiotic contamination.
Beta-lactam antibiotics have been implicated in a wide variety of hypersensitivity reactions such as in Multisystem (Anaphylaxis, Serum sickness-like reaction, Drug fever, Vasculitis and Generalized lymphadenopathy), Skin (Maculopapular/morbilliform eruption, Urticaria/angioedema, Stevens-Johnson syndrome, Toxic epidermal necrolysis, Contact dermatitis and fixed drug eruption), Bone Marrow (Hemolytic anemia, Thrombocytopenia, Neutropenia, Aplastic anemia and Eosinophilia), Lung (Pulmonary infiltrates with eosinophilia), Kidney (Interstitial nephritis and Nephrotic syndrome), Liver (Hepatitis) and in Heart Myocarditis. A study conducted in France showed that out of 1431 children, 227 (15.9%) were diagnosed allergic to beta-lactams. Pasteurization treatment (72°C/15sec) does not degrade beta-lactam antibiotics more than 1 percent. So the best way to avoid using antibiotics contaminated milk is to stop entry of antibiotic residues in milk supply chain. The only way to do so is to follow the withdrawal period of antibiotics used. Before withdrawal period, milk from treated animals must not be consumed.
Strict observation and monitoring of antibiotic residues can be helpful in restricting the entry of these residues into the milk supply system. It requires farmer’s awareness about the harmful effects of antibiotic residues and the creation of easy and cheap safe-level tests. Thus, a worldwide policy including education, monitoring, cheap and accurate tests and regulations must be designed to guarantee the supply of safe milk to the people worldwide.
SANA MOIN
UVAS, Lahore