Biotechnologia Acta (Dec 2019)
POST-HARVEST TREATMENT OF VEGETABLES WITH EXOMETABOLITES OF Nocardia vaccinii IMV B-7405, Аcinetobacter calcoaceticus IMV В-7241 AND Rhodococcus erythropolis IMV Ас-5017 TO EXTEND THEIR SHELF LIFE
Abstract
The aim of the work was to study the possibility of Nocardia vaccinii IMV B-7405, Acinetobacter calcoaceticus IMV B-7241 and Rhodococcus erythropolis IMV Ac-5017 supernatants usage with various concentrations of surfactants for post-harvest processing of vegetables. N. vaccinii IMV B-7405, A. calcoaceticus IMV B-7241 and R. erythropolis IMV Ac-5017 were grown on used sunflower oil and ethanol. For vegetables treatment, supernatants of the culture fluid with surfactant concentration of 0.01‒0.5 g/l were used. The concentration of surfactants was determined by the gravimetric method after extraction with Folch mixture. The total number of heterotrophic bacteria and fungi on the surface of vegetables was determined by the Koch method on meat-peptone agar and wort agar, respectively. It was shown that treatment of broccoli, Brussels sprouts, sweet pepper and tomatoes with N. vaccinii IMV B-7405, A. calcoaceticus IMV B-7241 and R. erythropolis IMV Ac-5017 supernatants was accompanied by 6‒17 and 8–50 times decrease of bacteria and fungi number on their surface, respectively, compared with that on the surface of vegetables washed with tap water. The possibility of double use of the same supernatant for various batches of vegetables washing was established. Non-treated and water-washed vegetables spoiled faster than those treated with surfactant-containing supernatants did. N. vaccinii IMV B-7405, R. erythropolis IMV Ac-5017 and A. calcoaceticus IMV B-7241 exometabolites used for treating vegetables to extend their shelf life have the following advantages in comparison with known microbial surfactants: they exhibit high antimicrobial activity when the surfactant concentration was sometimes lower and in the form of supernatant, which lets you exclude the expensive stage of isolation and purification of the target product from the technological process. In addition, surfactant-containing supernatants are highly effective in their repeated use.
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