Articles, Conference and Workshop Papers Collection

Permanent URI for this collectionhttp://10.10.97.169:4000/handle/123456789/1174

Browse

Browsing Articles, Conference and Workshop Papers Collection by Subject "Aspergillus flavus"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Correlation between aspergillus flavus fungal biomass and aflatoxin contamination in harvested maize: insights from Kenya and Tanzania
    (Tehran university of medical sciences., 2023) Temba, Benigni Alfred; Bakari, Gaymary George; Mgonja, Frida Richard; Mushi, James Richard
    Controlling the occurrence of aflatoxins in foods must be accompanied by managing the fungi responsible for their production. The abundance and diversity of aflatoxin-producing Aspergillus flavus are responsible for the accumulation of these toxins in crops, posing a persistent threat to public health and the economy in tropical developing countries. A study was conducted to investigate the occurrence and level of A. flavus and relate them to aflatoxin levels in maize in Kenya and Tanzania. A total of 786 maize samples were collected during harvesting in selected areas of the two countries for analysis. The fungal abundance in the samples was measured as the amount of fungal DNA relative to maize DNA. This was accomplished by quantifying the fungal DNA using qPCR, targeting the internal transcribed spacer (ITS) gene, while the maize DNA was quantified through the alpha-tubulin gene, the two genes known to be conserved. Aflatoxins were quantified using ultra-high performance liquid chromatography, coupled with ultra-high sensitivity, ultra-fast triple quadrupole tandem-mass spectrophotometer. A. flavus was detected in 88.5% of the 786 tested samples, and the average fungal load for these samples (expressed as the log host/pathogen ratio) was 5.53. Aflatoxin occurrence was positive in 31.9% of the samples, with an average level of 2.3 ± 0.643 ppb. The study established a positive relationship between the occurrence and level of aflatoxin B 1 and the presence and biomass of A. flavus, which was statistically proven. These findings emphasize the need to place substantial attention on preharvest control of A. flavus in cereal fields as an effort to control the accumulation of aflatoxin B1 in foods.
  • Thumbnail Image
    Item
    Photodynamic inactivation of Aspergillus flavus mediated by Bidens pilosa extract
    (Tanzania Veterinary Journal, 2015) Temba, B. A.; Fletcher, M. T.; Fox, G. P.; Harvey, J. W.; Sultanbawa, Y.
    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.