Milk from cows treated with antimicrobials cannot be delivered to a dairy due to the presence of antibiotic residues, because such milk poses a health risk to consumers and prevents bacteria from processing the milk to form cheese and yogurt. However, treated cows still need to be milked, and occasionally this milk is mixed by mistake with milk from healthy cows, thereby contaminating the entire batch, according to an announcement from Cordis, the European Commission's primary public portal of information on all European Union-funded research projects.

When the tanker collects the milk from the farmer, it is mixed with milk from several other herds, thus contaminating an entire load, the announcement said. Moreover, tests for antibiotic residues are not usually performed until the milk tanker arrives at the dairy plant.

If the contents are contaminated by milk from even a single treated cow, the whole load must be discarded and the tanker sent for special cleaning, causing delays in the next milk collection.

According to Cordis, the milk quality antibiotic sensor (MILQAS) project addressed this challenge, developing a working prototype for a handheld measuring device that monitors the presence of antibiotics.

“We designed a unit for the electrochemical analysis of milk, including software and an associated app,” said Dr. Johannes Daprà, project coordinator and chief scientific officer of Plastisens ApS, in Denmark.

In the EU, the fine and costs for contaminating milk with antibiotics are in the region of 15,000 euros, and lost milk represents a considerable waste of energy, while the associated greenhouse gas emissions also affect the environment. This could be prevented by testing for antibiotic residues before collection by the milk tanker rather than at the dairy plant, the announcement said.

Current methods for measuring antibiotics are not feasible for use directly on the farm. Therefore, MILQAS developed sensor chips together with a handheld reader that can measure the level of antibiotics in milk within a few minutes. The chip is made from inexpensive, disposable materials and is intended for one-time use, Cordis said.

Major benefits

"The entire electrode system is printed on polymer foil, making the printing process cheap and easily scalable, with only very small amounts of more expensive materials for electrodes and connections needed,” Daprà explained.

Researchers also developed a smartphone application for Android and IOS with connection to the reader device, which displays the obtained data for fast and easy evaluation at the dairy farm.

By measuring antibiotic levels close to their source, less milk is wasted, and less energy is consumed due to greater efficiency in milk production. Therefore, MILQAS will help reduce food waste and improve food safety in the dairy sector, Cordis said.

“Our estimation is that in the EU, about 6,000 truckloads (each around 30,000 liters) of milk are discarded every year due to antibiotic contamination. This amount can be significantly reduced by testing the milk before loading it into the tanker, thereby preventing cross-contamination,” Daprà reported.

The main beneficiaries of the technologies will be the dairy industry and farmers because of higher yields, reduced wastage and reduced insurance costs. Furthermore, the technique used for measuring antibiotics is not limited to milk and can be adapted for use in other markets, like the veterinary sector and food production.

“The technology platform can be adapted for testing for other contaminants in both liquid and solid samples,” Daprà pointed out.