Simplified Test Offers Rapid On-Farm Detection of Mastitis-Causing E. coli in Cow's Milk

Researchers at Charles Sturt University in Australia developed a simplified testing method to quickly detect Escherichia coli (E. coli) bacteria in cow's milk. Using a simple DNA preparation technique called HotSHOT paired with loop-mediated isothermal amplification (LAMP), a visual color-changing assay, the researchers created a low-cost testing procedure that works without complex laboratory equipment. This diagnostic tool could help dairy farmers to rapidly identify infections for sustainable herd management.

In dairy cattle, E. coli is a major cause of mastitis, but conventional molecular tests require costly kits and laboratory equipment. Direct boiling of raw milk is ineffective because its fats and proteins interfere with DNA amplification. To overcome this, raw milk was mixed directly with an alkaline lysis solution and a neutralizing buffer, then subjected to a 10-minute heat treatment at 90°C to break open bacteria right inside the sample. The extracted DNA within the treated milk was subsequently tested using a visual LAMP assay targeting the uidA gene, which turns from pink to yellow in the presence of E. coli.

The LAMP assay accurately identified 88.2% of positive mastitis cases, while PCR identified 100% with zero false positives in laboratory trials. Because active infections typically have a high bacterial load, the test reliably meets the threshold for on-farm decisions. Although the crude DNA extracts resulted in slightly lower sensitivity than laboratory PCR, the method exchanges peak analytical sensitivity for a low-cost, on-farm setup that could operate without the need for highly specialized lab equipment.

For more information, read the full study in Veterinary Research Communications.