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A team from the Consejo Superior de Investigaciones Científicas (CSIC) has developed a laboratory method to detect antibiotic residues in milk. The system, which can be implemented in laboratories exceeds speed and sensitivity to the current methods: it identifies up to 10 different antibiotics in 15 minutes. Its sensitivity is also extraordinary: the ability to detect minute amounts of antibiotic to 0.09 nanograms per milliliter, well below the maximum concentrations allowed by the EU, which is currently between 100 and 4 nanograms per milliliter of milk, depending on the antibiotic.

The method, published in the journal Analytical Chemistry as one of the outstanding number, has been developed by researchers at the Institute of Environmental Assessment and Water Research (CSIC) in Barcelona, along with an investigator from the analytical instrumentation company Spark Holland BV

To test and validate the system, the researchers analyzed 20 samples of real milk. Of these, 15 contained at least one of the antibiotic tested, but only one sample had levels that exceeded the maximum permissible limits.

As explained by one of the authors of the study, researcher Damian CSIC Barceló, "This is a method that streamlines the process of detection and identification of antibiotics in milk samples from cows.

It is ideal for companies in the food industry and laboratories, to identify the adulteration of milk freshly collected and then used to produce dairy products. "

The new detection system is specific for betalactímicos, a group of antibiotics that includes up to six penicillins such as amoxicillin or cloxacillin and four cephalosporins. The betalactímicos constitute one group of antibiotics used in the beef sector. Are provided for treating and preventing diseases such as bovine mastitis and pneumonia. In some cases continue to be used as an illegal growth promoters, a practice banned by the EU for some years. To limit exposure to the betalactímicos through food, the EU established in 2002, maximum permitted limits for each of these antibiotics.

There are currently kit type systems to control the spot where the milk is antibiotic residues. Are very useful as a warning system, but inaccurate, can sometimes give false positives. Furthermore, the existing laboratory methods are very expensive, so few facilities available. "The system developed in this work is more affordable, so it is expected that most laboratories can implement. Another advantage of the developed method is the reduction in the time of preparation of samples," explains Barceló.

The presence of antibiotic residues in milk is a health and economic problem. Have been documented cases of allergic reactions caused by antibiotics in milk. May also contribute to the spread of bacteria resistant to antibiotics used in human medicine. On the other hand, when the milk contained traces of antibiotics, the fermentation process for yogurt or cheese is severely affected, resulting in considerable economic loss for businesses.