The somatic cell count device. Credit: Yathirajarao Tammineni
A portable and low-cost device can rapidly detect and count somatic cells in raw milk1. Somatic cells are immune cells that rush into the infected mammary gland of a dairy animal such as a cow.
A high somatic cell count signals mastitis — a bacterial infection that spoils milk, reduces its shelf life and harms animal health.
The device, called QuantM, designed by a team at the National Institute of Animal Biotechnology in Hyderabad, contains iron oxide nanoparticles coated with a chemical that gives them a positive charge. When mixed with raw milk, the particles bind to the negatively charged somatic cells. Adding a surfactant makes the cells clump into visible aggregates.
A camera-fitted optical reader inside the device then photographs the clumps, runs the images through an algorithm and calculates the number of cells in the sample — within 10 minutes. QuantM can detect as few as 0.017 million cells per ml of milk with sensitivity and specificity comparable to flow cytometry but at much lower cost.
Early detection of mastitis reduces unnecessary antibiotic treatments, slowing the spread of antimicrobial resistance that can spill over to humans, says lead researcher Pankaj Suman.
