MaNEP e-Newsletter MaNEP Nr. 18
Free Column – page 4

MaNEP materials used in sensors for the Food Industry: the PURVEGE project

The shelf life of fruits and vegetables is a major issue for the food industry. The losses due to the proliferation of microbes and bacteria are considerable, and there is a pressing demand for cleaning and decontamination processes for fresh vegetables in general.
By Dr Jorge Cors, MaNEP/DPMC at UniGE
Jorge CorsThe goal of the PURVEGE project was to demonstrate the feasibility of a new physico-chemical process involving the combined use of UV radiation and ozone.

The PURVEGE project was initiated in 2006 in the framework of the Swiss-French cooperation programme INTERREG IIIA. It involved the Laboratoire de Recherche en Génie Alimentaire LRGIA (Université Claude Bernard Lyon 1), the Technopole ALIMENTEC, EREO SAS, HEV Technologies du Vivant (Sion) and the DPMC/MaNEP from the University of Geneva.

Key steps in the process were the exposure of the cleaning water to UV radiation followed by the application of ozone. The concentration of ozone appeared as a key parameter in the process since it had to be monitored at several measuring points in the laboratory prototype.

This was a great opportunity to put at work the know-how of the DPMC in transition-metal oxides ozone sensors. Indeed resistive sensors based on MoO3 nanorods (from the Laboratory of Inorganic Chemistry of the ETH Zürich) are very sensitive to ozone.

The nanorod-based sensors from MaNEP can be used as detectors to monitor ozone leaks from such installations. Although the selectivity of such devices must still be improved, the working environment of the cleaning system is free from interfering gases. This will not be the case for the automotive industry, for example.

The PURVEGE decontamination prototype was successfully tested with several vegetables. In particular, the shelf life of tomatoes and apricots was extended considerably.

The main results of the project were presented last June to the press and industry at the LRGIA in Bourg-en-Bresse. Up-scaling tests have been scheduled with industrial partners, and the scientific contribution of the DPMC/MaNEP was highly appreciated.

The PURVEGE prototype