Five-minute dairy milk scan is goal of surface plasmon resonance sensor

A new SPR optical sensor aims to find contaminants in milk in five minutes versus days using conventional methods.

A new optical sensor that can check the presence of contaminants in milk and produce a detailed reading in 5 minutes, is set to dramatically reduce costs, wastage and antibiotic use linked to the production, quality control, and processing phases in the dairy industry. Scanning milk for 2 proteins and 10 contaminants simultaneously, the optical sensor will take measurements directly on-site at each point of the long and logistically-spread milk value chain and deliver a detailed reading in about 5 minutes. Using the collected information, companies can prevent contaminants, such as antibiotics and aflatoxin, from entering the food chain.

The system works by exploiting highly miniaturized organic optoelectronic devices with a grating that supports surface plasmon resonances (SPR). These SPRs are waves of free electrons at the surface of a metal. They are extremely sensitive to binding events occurring on the surface and can be excited and detected by a light beam impinging on the surface. Then, a change in the reflected intensity carries out information on the "in situ" interaction of specific, pre-programmed receptors with selected bacteria, toxins, antibiotics and, in general, with contaminants.

Across dairy farms today standard tests take days to perform, whereas this new palm-sized sensor will be the easiest way to check the presence of milk components (such as kappa-casein proteins) that are quality parameters for milk and other dairy products. The same readout can help prevent food poisoning outbreaks like Staphylococcal enterotoxins (SEs) while at the same time predicting milk quality (Kappa Casein) and cow health (lactoferrin).

"With this sensor system," says project coordinator Stefano Toffanin, researcher at the Italian National Research Council (CNR) in Bologna, "farmers will be given an insight to understand the health of their cows, dairies will be able to make instant judgements about the contaminants in milk and processors can keep an eye on quality control."

The goal of the sensor is for milk samples to be analyzed by both technicians at the dairy plant level and farm-based users who are not experts, within a 5-minute period. Used as an offline, handheld tool by non-specialists and technicians alike, the miniaturized sensor system can be integrated into a milking machine for inline detection.

Depending on the company and country, dairy processors will usually pay more for higher-fat and high-protein milk. Kappa Casein B type is a milk protein that is extremely important in cheese making, for its ability to clot and form curds. Farmers can use this new optical sensor system to assist in breeding programs to deliver more valuable milk by identifying cows that produce high value Kappa Casein B type proteins.

"Detection and investigation of contaminants in fluids is a rapidly growing field in SPR bio sensing. Until recently, optical constrains, high costs, and limitations in the detected parameter number prevented the use of SPR outside of a laboratory. Within our unique integrated sensing architecture, MOLOKO can deliver results in minutes, for advanced dairy analysis."

Going by the acronym MOLOKO (, meaning Multiplex phOtonic sensor for pLasmonic-based Online detection of contaminants in milK, the consortium developing the sensor system expects to have a prototype ready in 3 years. MOLOKO is a Photonics Public Private Partnership project that secured nearly $7 million dollars (6 million euro) of EC funding via the Horizon 2020 work programme.

SOURCE: Photonics21;

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