Mould contamination of ready-to-eat cereal-based foods retailed in Lesotho with special reference to toxigenic Aspergillus flavus

Samples belonging to four different brands (Instant Morvite^TM, E-Papa^TM, Ace Instant Porridge^TM and Roasted Morvite^TM) of ready-to-eat fortified cereal-based foodstuffs imported from the Republic of South Africa were bought from different retail outlets in the Roma valley, Lesotho and examined for contamination with moulds. All (100%) of Roasted Morvite^TM and E-Papa^TM examined were contaminated with fungi. The greatest average fungal load (1.33 x 10⁵) was recorded on Roasted Morvite^TM samples. Although all the E-papa^TM samples were contaminated, the upper limit average mould load (1.0 x 10⁴)was the lowest compared to other brands that were analysed. A total of 226 isolates belonging to five different genera ( Aspergillus

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, Penicillium

, Cladosporium

, Wallemia

and unidentified genus) were recovered. For each of the brands assessed, average mould counts for some samples were above maximum permissible limits (10³ CFU/g) established by World Food Programme guidelines for fortified blended foods. Aspergillus and Penicillium isolates exhibited greatest fungal population densities, 52.7%, 36.3%, respectively. Wallemia was the least frequently isolated genus in this study; only four isolates (1.8%) recovered from all the samples investigated belonged to this genus. Of the Aspergillus species isolated, A. niger had the greatest relative density (39.5%) followed by A. flavus (37.8%), while Aspergillus amstelodami

and unidentified Aspergillus species had the lowest. Of the 22 A. flavus isolates tested for sclerotia production potential, 18 produced large sclerotia with average diameter > 400.02±82.61 on Czapek solution, agar. Ten (56%) of these isolates were toxigenic as evidenced by formation of a blue fluorescence on the reverse of the plates when observed under UV (365 nm). It was concluded that the detection of above -permissible limits levels of moulds and aflatoxigenic fungi in some samples analysed presents a risk to consumers' health. It is, therefore, suggested that a statutory, independent and science-based body dedicated to protecting public health and consumer interest in the area of food safety and hygiene be established. The main function of such a body would be to take all reasonable steps to ensure that food produced, distributed or marketed in Lesotho meets the highest standards of food safety and hygiene available.