Bacterial contamination of milk presents a challenge for food industry and is a risk from point of the consumers. Most of the currently available detection methods for bacterial contaminants are limited in their generic usability. They are time consuming (conventional methods) and/or imprecise due to many limitations e.g. sensitivity, selectivity, cost, etc. (rapid detection methods). Methods which overcome these limitations are needed.

We demonstrate a novel liquid fingerprinting technology for detection of spiked contaminants in commercial quality milk. For this simulation of product hygiene failure, we used strains of Escherichia coli and Staphylococcus aureus.

This fingerprinting method relies on the combination of non-specific profiling and specific land-marking – “diagnosis now”. It is based on the use of long luminescence lifetime europium chelate label and individual cross-reactive modulators in an array form. Europium label signal, by default, is highly sensitive to the environment enabling the detection of the weak interactions between the label, the chemical modulators and the sample. The resulting TRF (time resolved fluorescence) signals from the array are used to generate a digital fingerprint that is representative for the given sample.

Using this method we are able to detect and identify at the level of 10,000 bacterial cells/ml in several types of milk (different fat and lactose content) within short time: 10–30 min.

Using milk as an example, we demonstrated that this uncomplicated, inexpensive and fast method gives a perspectives to be a potential tool for food diagnostic in quality control laboratories.