Pumpkins Hold the Key to Natural Disinfectants

In 2009, researchers from the Institute of Environmental Biotechnology Graz University of Technology (TU Graz), found that locally grown Styrian oilseed pumpkins, harboured specific bacterial communities that protected them from disease outbreaks. In recent years the plants had suffered significant weather damage and consequently came under heavy fungal attack. Plants that remained healthy were shown to have different bacterial communities to those that succumbed to disease.

Protective bacterial communities produced highly effective volatiles that inhibited the growth of both human and plant pathogens in laboratory experiments. “We continued to conduct research on the volatile substances of these bacteria to find out how they combat pathogens so effectively” said Gabriele Berg, head of the Institute of Environmental Biotechnology at TU Graz .  Analytical methods that allowed high-throughput screening for bioactive compounds were developed by Tomislav Cernava at the Institute for Environmental Biotechnology of TU Graz and published in the journal Frontiers in Microbiology. The composition of these volatile mixtures were gradually deciphered, and a previously uncharacterized diazine group with highly pronounced antimicrobial effects was identified.

Following this discovery, work focused on transferring this natural antimicrobial to industrial applications including shelf-life extending formulations for industrial bakeries and meat processing facilities. Specific derivatives were also shown to be highly promising surface disinfectants and so trials were conducted with biotic surfaces such as eggshells.

Microbial contamination can be a real challenge for egg hatcheries. To overcome the problem, formaldehyde fumigation of the eggs has been common practice in European large-scale hatcheries for many years. The practice is perfectly legal, however it can prove problematic and hazardous for local residents. Describing the problems, Tomislav Cernava commented “Formaldehyde evaporates quickly and you can’t control it completely in large-scale hatcheries – some gas always escapes”. Formaldehyde is carcinogenic and harmful to the environmental and so the EU has been searching for an effective alternative for the treatment of hatching eggs.

In pre-industrial scale applications for the decontamination of eggshells, the Institute of Environmental Biotechnology of TU Graz in collaboration with the Austrian Centre of Industrial Biotechnology showed that the novel surface treatment eliminated up to 99.6 % of germs. This data is comparable to conventional formaldehyde treatments and thus offers a promising and non-toxic replacement. Another advantage of this substance is that it is liquid at room temperature, but also evaporates easily, meaning the same equipment can be used that currently is for fumigation with formaldehyde. The results have just been published in the scientific journal Scientific Reports. As a next step, tests must be conducted on a large scale. It is hoped that these antimicrobial products could be made available to the health sector in the future.