Through a highly sensitive test, scientists found a host of chemicals used to treat illnesses in animals and people in samples of cow, goat and human breast milk, Daily Mail reported.
Though the doses of drugs were far too little to create an effect on anyone drinking them, the results highlight how man-made chemicals were now found throughout the food chain.
The highest quantities of medicines were found in cow’s milk.
Researchers believe some of the drugs and growth promoters were given to the cattle, or got into milk through cattle feed or contamination on the farm.
A Spanish-Moroccan team analysed 20 samples of cow’s milk bought in Spain and Morocco, along with samples of goat and breast milk.
Their breakdown, published in the Journal of Agricultural and Food Chemistry, revealed that cow’s milk contained traces of anti-inflammatory drugs niflumic acid, mefenamic acid and ketoprofen – commonly used as painkillers in animals and people.
It also contained the hormone 17-beta-estradiol, a form of the sex hormone oestrogen.
The researchers claim their new 30-minute test is the most sensitive of its kind. If the findings are true for Spanish and Moroccan milk, they could equally be true for milk produced in Britain and northern Europe.