Last week, there was European Antibiotics Awareness day. So, I took this opportunity to discuss the story that sometimes goes around on social media that milk is full of antibiotics nowadays.
So can there be antibiotics in milk? Yes, there can. If cows have an infection, they are treated with antibiotics, just like us humans. An important reasons that dairy cows get treated with antibiotics is an infection in the udder. The antibiotics used for this treatment can end up in the milk. The milk of cows treated with antibiotics should thus be collected separately and not go into the milk tank, to prevent contamination of the milk in the tank.
Because dairy processor want to be sure about the absence of antibiotics, every individual milk delivery is checked for the presence of antibiotics, before the milk is unloaded at the factory. If milk is found to be contaminated with antibiotics, the milk is destructed and the farmer get a financial penalty.
Besides human health, there is a second reason why dairy factories strictly control the absence of antibiotics, which is the effect it has on fermentation. Many dairy products (e.g. yoghurt and cheese) are made by fermentation, which is a process in which bacteria grow in the milk to achieve the specific taste & texture required. These bacteria used for fermentation do not grow if antibiotics are present. So that is an important reason to check every individual batch of milk delivered to the factory on the presence of antibiotics.
In conclusion, because every individual batch of milk is checked to confirm absence of antibiotics, milk is not a source of antibiotics in the human diet.
Kasper Hettinga, November 2016