Potential Control of Mycotoxigenic Fungi and Ochratoxin A in Stored Coffee Using Gaseous Ozone Treatment
The objective of this study was to examine the effect of treatment of Arabica green coffee beans with gaseous ozone (O<sub>3</sub>) for the control of ochratoxigenic fungi and ochratoxin A (OTA) contamination by <i>Aspergillus westerdijkiae</i>, <i>A. ochraceus</i>...
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| Format: | Article |
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MDPI AG
2020-09-01
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| Series: | Microorganisms |
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| Online Access: | https://www.mdpi.com/2076-2607/8/10/1462 |
| _version_ | 1797552806495780864 |
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| author | Asya Akbar Angel Medina Naresh Magan |
| author_facet | Asya Akbar Angel Medina Naresh Magan |
| author_sort | Asya Akbar |
| collection | DOAJ |
| description | The objective of this study was to examine the effect of treatment of Arabica green coffee beans with gaseous ozone (O<sub>3</sub>) for the control of ochratoxigenic fungi and ochratoxin A (OTA) contamination by <i>Aspergillus westerdijkiae</i>, <i>A. ochraceus</i>, and <i>A. carbonarius</i> during storage. Studies included (i) relative control of the populations of each of these three species when inoculated on irradiated green coffee beans of different initial water availabilities using 400 and 600 ppm gaseous O<sub>3</sub> treatment for 60 min at a flow rate of 6 L<sup>−1</sup> and on OTA contamination after 12 days storage at 30 °C and (ii) effect of 600 ppm O<sub>3</sub> treatment on natural populations of green stored coffee beans at 0.75, 0.90, and 0.95 water activity (a<sub>w</sub>) or with additional inoculum of a mixture of these three ochratoxigenic fungi after treatment and storage for 12 days at 30 °C on fungal populations and OTA contamination. Exposure to 400 and 600 ppm O<sub>3</sub> of coffee beans inoculated with the toxigenic species showed that there was less effect on fungal populations at the lowered a<sub>w</sub> (0.75). However, toxigenic fungal populations significantly increased 48 h after exposure and when stored at 0.90 and 0.95 a<sub>w</sub> for 12 days. All three species produced high amounts of OTA in both O<sub>3</sub> treatments of the wetter coffee beans at 0.90 and 0.95 a<sub>w</sub>. Gaseous O<sub>3</sub> (600 ppm) treatment of naturally contaminated green coffee beans had little effect on fungal populations after treatment, regardless of the initial a<sub>w</sub> level. However, after storage, there was some reduction (26%) observed in coffee at 0.95 a<sub>w</sub>. In addition, no fungal populations or OTA contamination occurred in the 0.75 and 0.90 a<sub>w</sub> treatments after exposure to 600 ppm gaseous O<sub>3</sub> and storage for 12 days. It appears that under wetter conditions (≥0.90–95 a<sub>w</sub>) it is unlikely that fungal populations and OTA contamination of stored coffee beans, even with such high O<sub>3</sub> concentrations would be controlled. The results are discussed in the context of potential application of O<sub>3</sub> as an intervention system for stored coffee post-fermentation and during medium term storage and transport. |
| first_indexed | 2024-03-10T16:06:18Z |
| format | Article |
| id | doaj.art-0d14bbbcc0934a01b8f8c767969342df |
| institution | Directory Open Access Journal |
| issn | 2076-2607 |
| language | English |
| last_indexed | 2024-03-10T16:06:18Z |
| publishDate | 2020-09-01 |
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| record_format | Article |
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| spelling | doaj.art-0d14bbbcc0934a01b8f8c767969342df2023-11-20T14:52:04ZengMDPI AGMicroorganisms2076-26072020-09-01810146210.3390/microorganisms8101462Potential Control of Mycotoxigenic Fungi and Ochratoxin A in Stored Coffee Using Gaseous Ozone TreatmentAsya Akbar0Angel Medina1Naresh Magan2Applied Mycology Group, School of Water, Energy and Environment, Cranfield University, Cranfield, Bedfordshire MK43 0AL, UKApplied Mycology Group, School of Water, Energy and Environment, Cranfield University, Cranfield, Bedfordshire MK43 0AL, UKApplied Mycology Group, School of Water, Energy and Environment, Cranfield University, Cranfield, Bedfordshire MK43 0AL, UKThe objective of this study was to examine the effect of treatment of Arabica green coffee beans with gaseous ozone (O<sub>3</sub>) for the control of ochratoxigenic fungi and ochratoxin A (OTA) contamination by <i>Aspergillus westerdijkiae</i>, <i>A. ochraceus</i>, and <i>A. carbonarius</i> during storage. Studies included (i) relative control of the populations of each of these three species when inoculated on irradiated green coffee beans of different initial water availabilities using 400 and 600 ppm gaseous O<sub>3</sub> treatment for 60 min at a flow rate of 6 L<sup>−1</sup> and on OTA contamination after 12 days storage at 30 °C and (ii) effect of 600 ppm O<sub>3</sub> treatment on natural populations of green stored coffee beans at 0.75, 0.90, and 0.95 water activity (a<sub>w</sub>) or with additional inoculum of a mixture of these three ochratoxigenic fungi after treatment and storage for 12 days at 30 °C on fungal populations and OTA contamination. Exposure to 400 and 600 ppm O<sub>3</sub> of coffee beans inoculated with the toxigenic species showed that there was less effect on fungal populations at the lowered a<sub>w</sub> (0.75). However, toxigenic fungal populations significantly increased 48 h after exposure and when stored at 0.90 and 0.95 a<sub>w</sub> for 12 days. All three species produced high amounts of OTA in both O<sub>3</sub> treatments of the wetter coffee beans at 0.90 and 0.95 a<sub>w</sub>. Gaseous O<sub>3</sub> (600 ppm) treatment of naturally contaminated green coffee beans had little effect on fungal populations after treatment, regardless of the initial a<sub>w</sub> level. However, after storage, there was some reduction (26%) observed in coffee at 0.95 a<sub>w</sub>. In addition, no fungal populations or OTA contamination occurred in the 0.75 and 0.90 a<sub>w</sub> treatments after exposure to 600 ppm gaseous O<sub>3</sub> and storage for 12 days. It appears that under wetter conditions (≥0.90–95 a<sub>w</sub>) it is unlikely that fungal populations and OTA contamination of stored coffee beans, even with such high O<sub>3</sub> concentrations would be controlled. The results are discussed in the context of potential application of O<sub>3</sub> as an intervention system for stored coffee post-fermentation and during medium term storage and transport.https://www.mdpi.com/2076-2607/8/10/1462control<i>Aspergillus</i> section <i>Circumdati</i>section <i>Nigri</i>interventionochratoxin Acoffee beans |
| spellingShingle | Asya Akbar Angel Medina Naresh Magan Potential Control of Mycotoxigenic Fungi and Ochratoxin A in Stored Coffee Using Gaseous Ozone Treatment Microorganisms control <i>Aspergillus</i> section <i>Circumdati</i> section <i>Nigri</i> intervention ochratoxin A coffee beans |
| title | Potential Control of Mycotoxigenic Fungi and Ochratoxin A in Stored Coffee Using Gaseous Ozone Treatment |
| title_full | Potential Control of Mycotoxigenic Fungi and Ochratoxin A in Stored Coffee Using Gaseous Ozone Treatment |
| title_fullStr | Potential Control of Mycotoxigenic Fungi and Ochratoxin A in Stored Coffee Using Gaseous Ozone Treatment |
| title_full_unstemmed | Potential Control of Mycotoxigenic Fungi and Ochratoxin A in Stored Coffee Using Gaseous Ozone Treatment |
| title_short | Potential Control of Mycotoxigenic Fungi and Ochratoxin A in Stored Coffee Using Gaseous Ozone Treatment |
| title_sort | potential control of mycotoxigenic fungi and ochratoxin a in stored coffee using gaseous ozone treatment |
| topic | control <i>Aspergillus</i> section <i>Circumdati</i> section <i>Nigri</i> intervention ochratoxin A coffee beans |
| url | https://www.mdpi.com/2076-2607/8/10/1462 |
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