Sensor Foams: Easy Detection of Contaminations

One of the biggest challenges facing the food industry is guaranteeing food quality and safety. According to estimates, almost a third of all food produced worldwide is lost due to microbial infestation after harvest. During the supply chain, food can be contaminated by bacteria or pesticides (chemicals), resulting in illness and death. Each year, approximately 600 million people worldwide suffer from foodborne diseases. The detection of foodborne bacteria is therefore a growing global public health concern. Therefore, rapid and reliable detection of foodborne bacteria, pesticides and herbicides is needed urgently for the worldwide food industry including developing countries. Until now, detection methods are very time-consuming and expensive which makes it impossible to test large quantities of food quickly. In this project, we want to present a new, simple and innovative approach to the development of food sensors based on liquid foams that can be used to detect biochemical markers. Foams are very sensitive sensors, as even smallest changes in the composition of the surfactant solution drastically change the foam stability as well as the foamability. This change is visible with the naked eye and can be measured with a simple ruler. Due to the variation in foam volume, information about the presence and concentration of the biomarker can be obtained. To develop the sensor foams, we will use (i) different surfactant classes, (ii) different host molecules, and (iii) the binding affinity of bacteria to carbohydrate units. Foam-based sensors (sensor foams) offer a major advantage in terms of speed, cost and handling (direct on-site detection) compared to conventional methods. The aim of this project is to develop new methods using foams for the detection of bacteria in the food industry and to detect pollutants such as pesticides for environmental monitoring. Sensor foams can also be adapted and used for the detection of viruses and heavy metals, offering future perspectives.

Schad, T., Zauser, D., Fameau, A.-L., Stubenrauch, C.: Detection of lipase activity with liquid foams. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 683, 132995 (2024). https://www.sciencedirect.com/science/article/pii/S0927775723020794