Can microrobots improve the safety of dairy products?

Bovine mastitis produced by Staphylococcus aureus (S. aureus) can cause problems in milk quality and production due to the staphylococcal enterotoxins produced by this bacterium. This can have an economic impact on the dairy industry as the S. aureus can survive pasteurisation and thermal sterilisation processes, and the enterotoxins cannot be easily eradicated by common hygienic procedures once they are formed in dairy products.

According to FDA guidance, excessive numbers of S. aureus in raw milk or other dairy products, ie, greater than or equal to 10⁴ colony forming units per gram (cfu g⁻¹) indicates that the product was produced under unsanitary conditions. For this reason, efficient methods to isolate S. aureus bacteria from dairy products for removal or identification are in high demand and important for the dairy industry.

Now in research published in the journal Small, investigators have developed magnetic microrobots that can efficiently bind and isolate S. aureus.

Designed to enter hard-to-reach places within a milk production plant and operate wirelessly, the microrobots (called MagRobots) are loaded with antibodies (IgG from rabbit serum) to bind and isolate S. aureus from milk.

In the proof-of-concept study, the MagRobots were able to remove 3.42 10⁴ cfu g⁻¹ of S. aureus. The results indicate that the system can successfully remove S. aureus remaining after the milk has been pasteurised.

The study explained that this fuel-free removal system based on magnetic robots is specific to S. aureus bacteria and does not affect the natural milk microbiota or add toxic compounds resulting from fuel catalysis.

“This research brings microrobotics towards a new frontier: animal veterinary health and safe foods,” said corresponding author Martin Pumera, PhD, of the University of Chemistry and Technology Prague. “Microrobots, due to their size, are able to solve challenges faster than tradition technologies.”

According to the report, the system can be scaled up for industrial use in food production.

Image credit: iStock.com/dusanpetkovic