Aflatoxin-producing Aspergillus flavus from food samples in Nepal

Suprina Sharma; Dev Raj Joshi; Pramod Poudel; Supriya Sharma; Tika Bahadur Karki; Reshma Tuladhar; Reshma Tuladhar

doi:10.18502/ijm.v18i1.20942

Suprina Sharma Central Department of Microbiology, Tribhuvan University, Kirtipur, Nepal
Dev Raj Joshi Central Department of Microbiology, Tribhuvan University, Kirtipur, Nepal
Pramod Poudel Central Department of Biotechnology, Tribhuvan University, Kirtipur, Nepal
Supriya Sharma Central Department of Microbiology, Tribhuvan University, Kirtipur, Nepal
Tika Bahadur Karki Department of Biotechnology, Kathmandu University, Kavre, Nepal
Reshma Tuladhar Central Department of Microbiology, Tribhuvan University, Kirtipur, Nepal
Reshma Tuladhar Central Department of Microbiology, Tribhuvan University, Kirtipur, Nepal

DOI: https://doi.org/10.18502/ijm.v18i1.20942

Keywords: Aflatoxin; Aspergillus flavus; Cereals; Food safety

Abstract

Background and Objectives: Maize and peanuts, staple foods in Nepal, are highly susceptible to fungal contamination, particularly with aflatoxin-producing Aspergillus flavus. This study aimed to detect aflatoxin-producing A. flavus in maize and peanut samples collected from different regions of Nepal.

Materials and Methods: A total of 80 maize and 20 peanut samples were collected randomly from markets and households. Disinfected samples were inoculated on Potato Dextrose Agar and incubated at 28°C for 48 hours. A. flavus was identified by conventional cultural methods. Aflatoxin production was screened on Aspergillus Differential Medium (ADM) and con- firmed through Thin Layer Chromatography (TLC) and High Performance Liquid Chromatography (HPLC).

Results: Fungal contamination was detected in 67.0% of samples, with a significantly higher rate in household-stored sam- ples (p = 0.00039). A. flavus was the predominant species, particularly in maize (72.5%). Of 50 A. flavus isolates, 15 (30%) were aflatoxin positive on ADM, with 11 (73.3%) being confirmed by TLC. HPLC revealed AFB1 as the most prevalent in both maize and peanuts, while AFB2 was restricted to maize.

Conclusion: Maize and peanuts are highly susceptible to contamination with aflatoxin producing A. flavus in Nepal, partic- ularly in household-stored samples, emphasizing significant food safety concerns.