## 3 Results and Discussion
### Inhibition of A. niger Using SDBD Plasma  
It is generally recognized that microbial development is one of the main causes of palm date deterioration during storage. Therefore, deactivating or eliminating microorganisms is necessary for the safe storage of palm dates. Furthermore, non-thermal plasma is regarded as an effective method for surface decontamination of solid foods due to its inability to penetrate food samples deeper than a few micrometers [50]. Therefore, non-thermal plasma has no effect on the basic nutritious components of fresh fruits and vegetables [51].  
Therefore, we examined the impact of plasma treatment with SDBD on _A. niger_ extracted from several palm date varieties. The effects of different amounts of SDBD plasma on _A. niger_ after 15 days of incubation are shown in Table 1. As the duration of treatment increases, so does the ability of SDBD plasma to suppress _A. niger_. According to these findings, as plasma processing time increases, the number of _A. niger_ survivors (CFU/g) decreases. Moreover, the number of _A. niger_ survivors in control samples was 4.33 \(\pm\) 0.09 CFU/g. However, the number of _A. niger_ cells was reduced from 2.50 \(\pm\) 0.29 to 0.33 \(\pm\) 0.03 CFU/g when the SDBD plasma duration was extended from 1 to 3 min. The reduction of _A. niger_ at a 1 min exposure period was 1.83 logs, whereas the reduction at a 3 min exposure time was 4 logs. The results showed statistically significant (\(p<0.05\)) differences in the percentages of _A. niger_ survivors depending on how long they were treated with plasma.  
After 16 and 17 days of incubation, the numbers of _A. niger_ survivors were 4.47 \(\pm\) 0.03 and 4.50 \(\pm\) 0.00 CFU/g for control samples, respectively. In addition, when the exposure duration increases from 1 to 2.5 min, the number of _A. niger_ survivors increases throughout the incubation period. These findings indicate that the number of A. Niger survivors did not vary with incubation time when samples were treated for three minutes. After 16 and 17 days of incubation, the growth rate of _A. niger_ cells decreased gradually as the treatment period increased from 1 to 3 min, eventually reaching zero at 3 min. After 16 and 17 days of incubation, there was no statistically significant influence (_p_ > 0.05) on the growth rate of _A. niger_. It was found that 3 min of exposure to SDBD plasma was the best way to stop _A. niger_ from growing.  
Findings indicated that double jet argon plasma treatment suppressed _A. niger_ spores on date palm fruit slices [18]. In addition, they observed that non-thermal plasma reduced the ability of toxic fungi to produce mycotoxins in food and feed. The destruction of microorganisms by the use of non-thermal plasma is considered a complicated process due to the many factors involved [19].  
Reactive species generated by non-thermal plasma may significantly impair the cell integrity of microorganisms [44]. The polysaccharide-rich wall and outermost layer of microbial cells are directly altered by the reactive species generated by the non-thermal plasma. The organic molecules composing microbe cells are subjected to non-thermal plasma etching; as a result, the bonds of hydrocarbon compounds that comprise these organic compounds are destroyed [52]. Due to the easily reactive species with the broken links, these compounds will be etched more rapidly [53]. As a result, microorganism cells will be completely distracted.