Point of marketing survey for fungi associated with spoilage of oranges distributed at some depots in Kano Nigeria

Abstract

The recommendation of Food and Agricultural Organization (FAO) and the National Agency for Food, Drug Administration and Control (NAFDAC) prompts the current survey. This was with the aim of appraising health risk of oranges (Citrus sinensis) contaminated with fungi as well as generating a clue towards identifying the species involved. Accordingly, four markets, Naibawa, Jakara, Rimi and Brigade considered as Orange marketing depots in Kano Metropolis, Nigeria were screened. Five orange samples showing evidence of blemish such as moldy, decay and sunken rind were collected from each market. Samples were processed through decontamination of the outer rind with 75% ethanol, Fungal enumeration was carried out by plating on the potato dextrose agar (with chloramphenicol antibacterial) in duplicates and incubated aerobically at room temperature. Evidence of fungal growth was monitored for 1-7 days. Pure isolates of the fungi with the help of macroscopy and wet mount of mycelial specimen at x 40 objective power were conducted. Species were confirmed with the help of Atlas. Pathogenicity test was undertaken through Kotch’s postulates for symptoms of contamination and spoilage within 3-7 days. The findings confirmed involvement of Penicillium spp in 50%, Aspergillus spp in 25%, Fusarium spp at 17.5% frequency. Rhizopus spp showed 7.5% proportion. It was concluded that, oranges dispensed have shown a preponderance of spoilage fungi indicating health hazard, poor quality and can lead to economic losses. Better post-harvest and storage handling, Quarantine by Consumer Protection Agencies are recommended.