Fig 1.
Isolation of fungi on DRBC agar from green coffee (GC) beans samples.
Isolation of fungi on Dichloran Rose Bengal Chloramphenicol (DRBC) agar from green coffee (GC) beans samples. All green coffee beans samples yielded fungal communities, while none of roasted and soluble coffee samples showed fungal infection.
Table 1.
Mycotoxins levels (μg/kg) in marketed coffee samples.
Fig 2.
Effect of traditional roasting and brewing on OTA reduction (%) in naturally contaminated coffee beans.
Effect of traditional roasting and brewing on OTA reduction (%) in naturally contaminated coffee beans. Roasting OTA contaminated coffee beans at traditionally low, medium and high methods resulted in 15.17% (0.61 μg/kg), 46.78% (2.99 μg/kg) and 57.43% (3.82 μg/kg) reduction in mycotoxin contents, respectively. Brewing of OTA coffee samples already roasted at low, medium and high schemes resulted in further 43.57%, 14.11% and 7.28% reduction in mycotoxin, respectively.
Fig 3.
Effect of traditional roasting and brewing on AFs reduction (%) on naturally contaminated coffee beans.
Effect of traditional roasting and brewing on AFs reduction (%) on naturally contaminated coffee beans. The combined effect of roasting and brewing was 40.18% (34.65 μg/kg), 47.86% (41.17 μg/kg) and 62.38% (53.73 μg/kg) reduction in the AFs levels in the coffee samples roasted at traditionally low, medium and high methods, respectively.
Fig 4.
In vivo antagonistic activity of Bacillus simplex 350–3 volatiles against the growth of toxigenic fungi on infected coffee beans.
There was a significant growth of A. flavus (B) and A. carbonarius (D) on coffee beans in the absence of B. simplex volatile, compared to complete inhibition of fungi in A and B in the presence of bacterial volatile. BS (Bacillus simplex on tryptic soy agar); AF (coffee beans infected with Aspergillus flavus); PC (Plain coffee beans); AC (coffee beans infected with Aspergillus carbonarius); TSA (tryptic soy agar without any bacteria).
Table 2.
Effect of bacterial volatiles on the inhibition of mycotoxins synthesis by toxigenic fungi on coffee beans.
Table 3.
Analysis of B. simplex 350–3 volatiles through GC-MS/MS.