Israeli Scientists Engineer Glowing Bacteria to Detect Wine Spoilage in Real Time

Researchers at the Hebrew University of Jerusalem have developed a new biosensor that could help winemakers detect spoilage before it damages wine quality. The team, led by PhD student Yulia Melnik-Kesler and supervised by Prof. Yael Helman, created a living sensor using genetically engineered bacteria that emit light when they sense acetic acid, the main chemical responsible for turning wine into vinegar. Their findings were published in the journal Microbial Biotechnology.

Acetic acid is a key indicator of wine spoilage. When its concentration rises during fermentation, it can stall the process and give wine an unpleasant sour taste and smell. Traditionally, wineries rely on laboratory methods like gas or liquid chromatography to measure acetic acid levels. These tests are expensive, time-consuming, and require taking samples from the wine, making it difficult to monitor changes in real time.

The new biosensor offers a different approach. The researchers engineered bacteria to include a natural regulator called YwbIR, originally found in Bacillus subtilis. When these bacteria encounter acetic acid, YwbIR activates a gene that causes the bacteria to glow. The intensity of the light corresponds to the amount of acetic acid present, providing a clear and immediate signal.

In laboratory experiments, the biosensor responded strongly and predictably to acetic acid concentrations between 0 and 1 gram per liter—a range that is critical for winemakers. Spoilage typically begins when levels reach about 0.7 grams per liter. At these concentrations, the bacteria’s light output increased five- to eightfold, giving producers an early warning before the wine becomes undrinkable.

One notable feature of this technology is its ability to detect acetic acid not only in liquid but also in the air above the wine—known as the headspace—inside bottles or fermentation tanks. This means wineries could monitor for spoilage without opening containers or disturbing the wine. In tests with commercial red and white wines, the biosensor distinguished between normal and artificially spoiled samples within two hours by measuring changes in light emission.

The system also proved robust in high-alcohol environments, functioning accurately in wines with up to 14.5% alcohol content. Many traditional sensors struggle under these conditions because alcohol can interfere with their readings.

While this research focused on winemaking, the team believes their biosensor could have broader applications across industries that rely on fermentation, such as food production and biofuels. Acetic acid is also being studied as a biomarker for certain diseases, raising the possibility that future versions of this technology could be used for noninvasive medical diagnostics like breath analysis.

“This system allows us to detect acetic acid in real time, without complicated equipment or sample processing,” said Prof. Helman. “It opens the door to affordable, on-site monitoring of fermentation quality and may even support medical diagnostics based on volatile biomarkers.”

The development of this biosensor could help wineries catch spoilage early and avoid costly losses in flavor and quality. It may also offer a simpler and less expensive alternative to current laboratory testing methods, strengthening quality control across various fermentation-based industries.