Biocide Effect of Non-Thermal Atmospheric Pressure Plasma

Introduction. New methods of sterilization with non-thermal atmospheric pressure plasma remain an extremely relevant field of food science. The present research estimated the effect of non-thermal argon plasma on lactic acid bacteria obtained from walnuts. Study objects and method. The non-thermal a...

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Main Authors: Daria I. Petrukhina, Irina V. Polyakova, Sergei A. Gorbatov
Format: Article
Language:English
Published: Kemerovo State University 2021-03-01
Series:Техника и технология пищевых производств
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Online Access:http://fptt.ru/stories/archive/60/8.pdf
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author Daria I. Petrukhina
Irina V. Polyakova
Sergei A. Gorbatov
author_facet Daria I. Petrukhina
Irina V. Polyakova
Sergei A. Gorbatov
author_sort Daria I. Petrukhina
collection DOAJ
description Introduction. New methods of sterilization with non-thermal atmospheric pressure plasma remain an extremely relevant field of food science. The present research estimated the effect of non-thermal argon plasma on lactic acid bacteria obtained from walnuts. Study objects and method. The non-thermal argon plasma was generated by electrode discharge induced by a coaxial microwave plasmatron at atmospheric pressure. The discharge was generated in a special electrode construction. Its stability was achieved via low gas flow through the discharge gap. Argon consumption was 10 L/min. The study involved Lactobacillus plantarum and Lactobacillus mali in their natural association and vegetative form. Endo’s medium (Endo agar) was inoculated with lactobacilli. 100 μl of the suspension were added into a Petri dish with nutrient medium and carefully rubbed with a spreader. The plates with Endo agar inoculated with lactobacilli were placed under plasma radiation at a distance of 45 mm. The biocidal effect of plasma radiation was estimated by the diameter of the affected areas. After the plasma treatment, the Petri dishes were incubated in an incubator for 24–48 h at 37°C, after which the diameters of the affected areas were measured again. Results and discussion. The paper introduces experimental data on the effect of argon plasma on lactobacilli isolated from food. After treating the surface of inoculated Petri dishes with non-thermal plasma for five minutes, the diameter of the inhibition zone reached the diameter of a Petri dish (80 mm) and exceeded the diameter of the spark gap of the plasma generator (36 mm). The temperature on the surface of the nutrient medium during plasma treatment was within the optimal temperature for lactobacillus growth, i.e. 37.3 ± 0.6°C, which excluded thermal effects. Only a few colonies survived a five-minute treatment. After one-minute treatment, the number of survived colony-forming units was considerably higher. Conclusion. Non-thermal argon plasma treatment proved effective in inhibiting the growth of gram-positive bacteria (Lactobacillus isolated from walnuts) on solid surfaces (agar plates). After five minutes of plasma treatment, the inactivated area (80 mm) exceeded the anode electrode cross section (36 mm) of the plasma generator.
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spelling doaj-art-dc91118ea8ed43efa0f5ffcfe078b8ec2025-08-20T02:44:09ZengKemerovo State UniversityТехника и технология пищевых производств2074-94142313-17482021-03-01511869710.21603/2074-9414-2021-1-86-97Biocide Effect of Non-Thermal Atmospheric Pressure PlasmaDaria I. Petrukhina0https://orcid.org/0000-0002-5790-9958Irina V. Polyakova1https://orcid.org/0000-0003-1602-7921Sergei A. Gorbatov2https://orcid.org/0000-0002-7373-8183Russian Institute of Radiology and Agroecology, Obninsk, RussiaRussian Institute of Radiology and Agroecology, Obninsk, RussiaRussian Institute of Radiology and Agroecology, Obninsk, RussiaIntroduction. New methods of sterilization with non-thermal atmospheric pressure plasma remain an extremely relevant field of food science. The present research estimated the effect of non-thermal argon plasma on lactic acid bacteria obtained from walnuts. Study objects and method. The non-thermal argon plasma was generated by electrode discharge induced by a coaxial microwave plasmatron at atmospheric pressure. The discharge was generated in a special electrode construction. Its stability was achieved via low gas flow through the discharge gap. Argon consumption was 10 L/min. The study involved Lactobacillus plantarum and Lactobacillus mali in their natural association and vegetative form. Endo’s medium (Endo agar) was inoculated with lactobacilli. 100 μl of the suspension were added into a Petri dish with nutrient medium and carefully rubbed with a spreader. The plates with Endo agar inoculated with lactobacilli were placed under plasma radiation at a distance of 45 mm. The biocidal effect of plasma radiation was estimated by the diameter of the affected areas. After the plasma treatment, the Petri dishes were incubated in an incubator for 24–48 h at 37°C, after which the diameters of the affected areas were measured again. Results and discussion. The paper introduces experimental data on the effect of argon plasma on lactobacilli isolated from food. After treating the surface of inoculated Petri dishes with non-thermal plasma for five minutes, the diameter of the inhibition zone reached the diameter of a Petri dish (80 mm) and exceeded the diameter of the spark gap of the plasma generator (36 mm). The temperature on the surface of the nutrient medium during plasma treatment was within the optimal temperature for lactobacillus growth, i.e. 37.3 ± 0.6°C, which excluded thermal effects. Only a few colonies survived a five-minute treatment. After one-minute treatment, the number of survived colony-forming units was considerably higher. Conclusion. Non-thermal argon plasma treatment proved effective in inhibiting the growth of gram-positive bacteria (Lactobacillus isolated from walnuts) on solid surfaces (agar plates). After five minutes of plasma treatment, the inactivated area (80 mm) exceeded the anode electrode cross section (36 mm) of the plasma generator.http://fptt.ru/stories/archive/60/8.pdflactobacilluswalnutscold plasmadecontaminationinactivationmicrowaveplasmatron
spellingShingle Daria I. Petrukhina
Irina V. Polyakova
Sergei A. Gorbatov
Biocide Effect of Non-Thermal Atmospheric Pressure Plasma
Техника и технология пищевых производств
lactobacillus
walnuts
cold plasma
decontamination
inactivation
microwave
plasmatron
title Biocide Effect of Non-Thermal Atmospheric Pressure Plasma
title_full Biocide Effect of Non-Thermal Atmospheric Pressure Plasma
title_fullStr Biocide Effect of Non-Thermal Atmospheric Pressure Plasma
title_full_unstemmed Biocide Effect of Non-Thermal Atmospheric Pressure Plasma
title_short Biocide Effect of Non-Thermal Atmospheric Pressure Plasma
title_sort biocide effect of non thermal atmospheric pressure plasma
topic lactobacillus
walnuts
cold plasma
decontamination
inactivation
microwave
plasmatron
url http://fptt.ru/stories/archive/60/8.pdf
work_keys_str_mv AT dariaipetrukhina biocideeffectofnonthermalatmosphericpressureplasma
AT irinavpolyakova biocideeffectofnonthermalatmosphericpressureplasma
AT sergeiagorbatov biocideeffectofnonthermalatmosphericpressureplasma