## 3 Results and Discussion
### In Vivo Experiment
#### 3.3.2 Effect of Photosensitization on AFB1 Production  
The initial concentration of AFB1 was below the limit of quantification (LOQ = 0.01 ug\(\cdot\)L\({}^{-1}\)) in all treatments and maize kernels. After seven days of incubation, AFB1 was still undetectable (below the LOQ) both in photosensitized and curcumin-treated maize kernels, whereas the control and the light treated ones showed AFB1 accumulation over incubation time. Furthermore, there were no differences (\(p>0.05\)) in AFB1 accumulation amongst the investigated maize varieties (Figure 6).  
From seven to fourteen days of incubation, a significant (\(p<0.05\)) increase in AFB1 concentration was observed in all treatments, except for the photosensitized kernels where AFB1 was still undetectable. The curcumin-treated kernels showed an increase by over 60-fold after 14 days of incubation, reaching more than 63 mg\(\cdot\)kg\({}^{-1}\) AFB1 in white, yellow and popcorn maize. On the other hand, the light-treated white kernels showed a 18-fold increase in AFB1 concentration after 14 days. Yellow and popcorn varieties showed a significant (\(p<0.05\)) increase to over 335.08 mg\(\cdot\)kg\({}^{-1}\) AFB1. The control was not different (\(p>0.05\)) from the light treatment in all three varieties.  
Findings from this study substantiate the potential of photosensitization as an effective clean green technology to decontaminate food and reduce mycotoxin exposure to consumers, which is in agreement with previous studies [4, 49]. Curcumin-mediated photosensitization has been reported to reduce the accumulation of AFB1 by 73% on maize kernel after 10 days of incubation at moist conditions [23]. In another study, the combination of blue light and toluidine blue-O, a synthetic photosensitizer, reduced the formation of alternaid by _Alternaria alternata_ by over 90% for isolates from squash, tomato, pepper and cucumber [49].  
Our results on AFB1 formation corroborates with the visual observations of mould growth on maize kernel. In photosensitized kernels, the colony-forming ability of _A. flavus_ was completely suppressed, and no fungal growth was visually observed on the maize  
Figure 6: Concentration of aflatoxin B1 on maize kernel after photosensitization (P\({}^{+}\)L\({}^{+}\)), photosensitizer (P\({}^{+}\)L\({}^{+}\)), light (P\({}^{o}\)L\({}^{+}\)) treatments and negative control (P\({}^{o}\)L\({}^{o}\)). Data are means \(\pm\) SE (\(n=3\)); means followed by different letters (lowercase letter for treatments in the same variety and uppercase letter for different periods in the same variety) are significantly different (\(p<0.05\)).  
samples even after 14 days of incubation at moist conditions. On the other hand, AFB1 was not detectable in curcumin-treated kernels after seven days of incubation, which is consistent with no fungal growth observation in the same period. It could be suggested that propylene glycol in curcumin solution is acting as a coating layer on the maize surface, encapsulating curcumin and releasing it throughout the seven days of incubation, which increases the contact time between curcumin and spores, reducing their viability. The antimicrobial properties of curcumin against different fungal pathogens, including _A. flavus_, have been documented in previous reports [50; 51; 52]. Additionally, soaking the kernels in curcumin solution might have partially washed the spores from the kernel surface reducing their concentration and delaying germination during the incubation period.