Tanzania Veterinary Journal (The Tropical Veterinarian), 2015; 30 (1): 42-50
Occurrence of mycotoxins in food and animal feeds poses major health risks to human and animals,
and effective control requires integration of crop management strategies both in the field and during
post-harvest storage and processing. Photodynamic inactivation is a novel light-based approach
which offers a promising alternative to conventional methods for the control of mycotoxigenic fungi.
An experimental study was conducted to assess the effectiveness of photoinactivation of Aspergillus
flavus, a major aflatoxin-producing fungal species, by photosensitization mediated by an extract of
the tropical plant Bidens pilosa. Photosensitization was conducted on fungal spores and hyphae in
solution using of 420 nm wavelength light at a dose of 60 J cm -2 combined with 0.25 and 0.5 mg ml -1
of the plant water extract. The numbers of viable spores and hyphae were reduced by 4 log colony
forming units (CFU ml -1 ) and this was affected by changing temperature but not pH. The findings of
this study indicate the potential of using photosensitization technique utilizing natural photosensitizers derived from locally available herbs to effectively control mycotoxins in feeds for
improved livestock production.