The High Valley of the Black River and Neuquén, Argentina, has traditionally produced great quality apples and pears; in order to preserve them, refrigerators, and often also chemical products, are used to protect the fruit against pathogens.
However, due to the need for sustainability and to avoid the presence of chemicals in food, alternative methods are being proposed to control these pathogens in a safer, cheaper and more effective way.
"The use of microorganisms to protect food is a promising alternative; yeasts are ideal because they are safe for human consumption," explains Marcela Sangorrín, CONICET researcher at the North Patagonia Multidisciplinary Institute for Research and Development (IDEPA, CONICET-UNCo) and director of the research group on yeast biodiversity and biotechnology.
Only a few organic control agents are currently available worldwide. "In our country, these have yet to be commercially registered," highlights Sangorrín. "Their use has been prevented by high import costs and inconsistent results against local pathogens," she explains.
The main goal is to find yeasts that are effective in delaying the decomposition process of fruits in the region. It is essential that organic control agents are adapted to the location where they are to be used. "The chances to find efficient microorganisms increase if we seek them in the same environment and fruit to which they will be applied," clarifies the researcher. "The idea is to find yeasts characteristic of our fruit and the region to obtain a fully natural product."
Research to develop yeasts adapted to local needs has been conducted since 2007.
The group selected the pathogens most found in fruit: Botrytis cinerea and Penicillium expansum, chosen for their aggressiveness and resistance to fungicides.
The fruit was treated with this form of organic control, applied by spraying, in the usual conditions for fruit processing and was later stored in a refrigerator. Two yeast strains were selected for their effectiveness against both pathogens and in this year's study they were used in combination with calcium chloride.
After 45 days, fungus-related illnesses were fully under control. After 90 days, the calcium chloride improved the effectiveness of the yeasts; one yeast controlled 80% and the other 91% of the illnesses.
CONICET and the National University of Comahue patented both yeasts in March this year.
"In addition to re-evaluating our data on other pear varieties, we would like to test if the yeasts are also effective on apples; this way we could formulate a product which would be effective to protect the region's two main fruit crops," concludes Sangorrín.
Source: Dicyt.com
Researchers obtained yeasts from water used in washing pears. Microorganisms such as yeasts, bacteria and fungus can be found on its surface.
The fruit was treated with this form of organic control, applied by spraying, in the usual conditions for fruit processing and was later stored in a refrigerator. Two yeast strains were selected for their effectiveness against both pathogens and in this year's study they were used in combination with calcium chloride.
After 45 days, fungus-related illnesses were fully under control. After 90 days, the calcium chloride improved the effectiveness of the yeasts; one yeast controlled 80% and the other 91% of the illnesses.
CONICET and the National University of Comahue patented both yeasts in March this year.
"In addition to re-evaluating our data on other pear varieties, we would like to test if the yeasts are also effective on apples; this way we could formulate a product which would be effective to protect the region's two main fruit crops," concludes Sangorrín.
Source: Dicyt.com
