Ozone and UV Mould & Bacteria Control
Gaseous ozone will effectively control mould and bacteria on various fruits and vegetables. The main benefit of using gaseous ozone is that mould and bacteria are controlled both in the air and on the surface of the product. The end result to the produce grower/packer is a dramatic reduction of product spoilage. Additionally, gaseous ozone oxidizes and destroys ethylene gas that is released when fruits and vegetables begin to ripen. Thus, the use of gaseous ozone can reduce ripening while in storage.
| Effect of 0.6 ppm Ozone on Germination of Wet Spores of Three Fungi at Room Temperature | |||||||||
Fungi | Ozone, Treatment hours | No ozone, hrs | |||||||
| 0.5 | 1 | 1.5 | 2 | 2.5 | 3 | 0.5 | 4 | 5.5 | |
| % spores remaining | |||||||||
| S. fructicola | 61 | 23 | 18 | 16 | 0 | 0 | 70 | 57 | 60 |
| P. expansum | …. | 69 | 50 | 3 | 0 | 0 | 68 | 65 | 70 |
| Macrosporium | 98 | 97 | 96 | 40 | 15 | 6 | 100 | 97 | 96 |
| Spore Counts in Ozone and Non-ozone Cold Storage Rooms for Apples | |||||
Storage Number | Temperature ΕF | Date | Ozone Conc’n, ppm | Total spores/yd3 atmosphere | |
| Ozone | No Ozone | ||||
| 1 | 40 | 11/22/40 | 1.5* | 16,000 | 1,380,000 |
| 1 | 40 | 12/26/40 | 1.5* | 2,760 | 4,280,000 |
| 2 | 32 | 2/26/41 | ….** | 910,000 | 1,111,000 |
| 3 | 32 | 11/18/40 | 0.4*** | 46,000 | …….. |
| 3 | 32 | 12/21/40 | 0.4 | 81,000 | …….. |
| * Ozone was used continuously in this room. | |||||
| ** Ozone was turned off when concentration could be smelled | |||||
| *** Ozone was used only for an hour or two each day. | |||||
EXAMPLES
Potato storage treatment will reduce or eliminate soft rot and pink rot, late blight and sprouting
Potatoes in storage for 6 months with ozone at the right levels will be of exceptional quality and the potatoes will not suffer any damage from ozone. These potatoes if used for chip production will be extremely white and “bad” potatoes would be controlled and will not affect adjacent potatoes. No sprouting will occur and the fry quality of any bin will be two weeks longer than normal.
CITRUS
Ozone at low concentrations greatly reduces the sporulation of green and blue mould.
#1 Low concentration of ozone for 12 hrs. per day results in spore control
#2 High concentrations of ozone for 12 hrs. per day will result in spore mortality
| Rating Criteria | ||||
| Worst | Normal | Ozone | Ozone | |
| External Defects | 15 | 10 | 3 | 0 |
| Internal Defects | 15 | 10 | 3 | 3 |
| Combined Total | 30″}”>>30 | 20 | 6 | 3 |
| Color | <60 | 65″}”>>65 | 69 | 70 |
