The ability of four strains of Aspergillus parasiticus (IMI 301 001) and two strains of Aspergillus flavus (IMI 300998) to produce aflatoxins on Nigerian groundnuts under varying conditions of temperature was studied. While all the A . parasiticus strains produced the four major aflatoxjns (Bl, B,, GI, G,), only aflatoxin B,, and B, were produced by the A. flawus strains used. The optimum temperature for aflatoxin production by both the fungal species was 30 "C with no toxin production a t 10 "C.
Saprophytic fungi including toxigenic species are implicated in spoilage of Nigerian groundnuts (Arachis hypogea LINN.) during storage ( BAMPTON 1963, ELDRIDGE et HARKNESS 1965). This is particularly so in the tropics where high ambient temperatures (28"-32 "C) and relative humidities ( 2 80%) enhance fungal colonization of post-harvest agricultural produce. This accounts for the potent mycotoxins (aflatoxins, gliotoxin, fumagillic acid etc.) often detected in these products on analyses. Apart from the health risks posed t o the consumers, mould infestation, of products such as groundnuts leads to the formation of free fatty acids (ffa) which impart a rancid flavour to the oil obtained from them. Indeed, the quality and invariably, the market value of this oil depends on the ffa content, oils with low ffa being of higher quality than those with high ffa content (KUKU and ADENIJI 1976, OGUNDERO 1981 a). I n an earlier report ( OGUNDERO 1981 b), the lipase activities of the fungal contaminants of Nigerian groundnuts were studied. This communication deals with the production of aflatoxins by toxigenic strains of Aspergillus flatus and A . parasiticus from Nigerian groundnuts. Studies are also made of the role played by temperature in this regard.