The efficacy of thin-film diamond coated electrodes (DiaCell<sup<®< sup=””> 101) for disinfection of water artificially contaminated with Penicillium digitatum and Pseudomonas spp. was tested. Electrolysis process was performed with different operation conditions: current densities set at 4, 8, and 12A and water flow rate at 150, 300, and 600 L/h. For both pathogens, the experiments were performed in water suspensions at a final concentration of 105 CFU/ml. Tap water was used as a control. The results showed that fungal spores and bacterial cells were affected by flow rate and current density applied. The higher the water flow rate the greater the inactivation of the two microorganisms which were completely suppressed at high recirculation flow (300-600 L/h/cell). Pseudomonas spp. cells were inactivated at the highest current density applied (8-12A) after 6 min of electrolysis, whereas for P. digitatum the complete inactivation was observed at the same current densities after 12 min. The results obtained suggest that the two parameters can be modulated in order to achieve significant suppression in relation to the target microorganism and to obtain an antimicrobial effect without generation of chlorine.</sup<®<>
The effect of electrolyzed oxidizing (EO) water in combination with ozone to control postharvest decay of tangerine cv. “Sai Num Pung” was investigated. The spore suspension containing 105 conidia ml−1 of Penicillium digitatum was prepared. EO water was generated by electrolysis of various concentrations of NaCl solution (5, 25, 50% and saturated NaCl). The spore suspension was inoculated into EO water and incubated at 27 °C for 1, 2, 4, 8 and 32 min. It was found that the EO water with saturated NaCl completely inhibited the spore germination of the fungus within 1 min. When the fruits inoculated with P. digitatum were washed in EO water at the same concentrations as previous experiment for 4, 8 and 16 min and stored at 5 °C for 18 days, it was found that immersion of the fruit in EO water for 8 min was the most effective to reduce disease incidences. Moreover, washing fruit in EO water and kept in a refrigerated chamber at 5 °C with continuous ozone exposure at a concentration of 200 mg l−1 for 2 h day−1 to extend storage life suppressed the disease incidence until 28 days. However, none of the treatments had any effect on the quality of fruit such as total soluble solids, titratable acidity, percent weight loss and peel color. Therefore EO water may be useful for surface sanitation and ozone has potential to control the recontamination of postharvest diseases in tangerine fruit in storage room.
Spores of Penicillium expansum, the primary organism responsible for the occurrence of patulin in
apple juice, were exposed to electrolyzed oxidizing (EO) water in an aqueous suspension and on wounded apples.
Full-strength and 50% EO water decreased viable spore populations by greater than 4 and 2 log units, respectively.
Although EO water did not prevent lesion formation on fruit previously inoculated with P. expansum, cross-contamination of wounded apples from decayed fruit or by direct addition of spores to a simulated dump tank was
substantially reduced. EO water, therefore, has potential as an alternative to chlorine disinfectants for controlling
infection of apples by P. expansum during handling and processing operations.