Researchers at Umeå University have recently developed a highly sensitive method for detecting bacterial spores — tough microorganisms that survive extreme conditions and can cause both food poisoning and infections. This method could help improve food safety and healthcare.

Bacterial spores are one of nature’s most resilient organisms. These tiny, seed-like structures form when bacteria enter a dormant state to survive unfavorable conditions. They can endure extreme environments, including boiling water, common disinfectants and radiation — conditions that would kill most bacteria. Their resilience and ability to reactivate when conditions improve make them a major problem in healthcare, agriculture and food production.

“In this interdisciplinary study, we have developed a new, ultra-sensitive method to detect bacterial spores by combining nanoscience and biophysics," says Jonas Segervald, a doctoral student at the Department of Physics, Umeå University. He is one of the researchers behind the new discovery, which was recently published in the scientific journal ACS Sensors.

The method uses gold nanorods and laser technology to amplify signals from a unique molecule found in spores. This technique, called surface-enhanced Raman spectroscopy (SERS), enables the identification of incredibly small amounts of chemicals — down to individual molecules. It allows for early detection of bacterial spores even at very low concentrations, which is important in many industries, as preventive measures can be applied at an early stage.

The method uses gold nanorods and laser technology to amplify signals from a unique molecule found in spores. This technique, called surface-enhanced Raman spectroscopy (SERS), makes it possible to detect incredibly small amounts of chemicals — down to individual molecules. This sensitivity makes it possible to detect bacterial spores in very small amounts, which is important for many industries. Early detection helps prevent contamination before it spreads, allowing for quick action to stop it.

“Spores are highly problematic in hospitals and the food industry, as they can cause recurring contamination by attaching to surfaces and equipment, leading to illness, spoilage and costly cleaning measures,” says Dmitry Malyshev, staff scientist at the Department of Physics and co-author of the article.

One promising use of this new method is in the dairy industry, where bacterial spores, particularly from Bacillus species, pose a significant risk. Contamination in dairy production lines can lead to spoilage, product recalls and potential health risks. As milk and dairy products are a central part in Sweden's diet, ensuring a high level of food safety is a top priority. In line with this goal, the researchers successfully detected spores in a contaminated sample of milk, demonstrating the method’s potential in improving food safety.

“Our method offers enhanced sensitivity, allowing us to detect much smaller amounts of bacterial spores than previously possible. Although we are still in the early stages, we are actively working to improve this technology into a practical sensor that can be customized for industries at risk of spore contamination," says Jonas Segervald.