Comparative subchronic toxicity studies of nixtamalized and water-extracted Fusarium moniliforme culture material

Fumonisins are mycotoxins produced by Fusarium moniliforme, F. proliferatum and other Fusarium species, which are commonly found on corn, cause a variety of species-specific toxicoses, and have been linked to human oesophageal cancer in areas of southern Africa and China where corn is a dietary staple. The effect of nixtamalization, the process by which masa flour is produced by alkaline hydrolysis of corn, on the organ-specific toxicity of F. moniliforme culture material containing fumonisin B1 (FB1) was studied and the effectiveness of nixtamalization and water extraction for detoxifying culture material was compared. Male rats (n = 10/group) were fed diets containing 5% culture material equivalent weights of nixtamalized culture material (NX diet) providing 58 ppm hydrolysed FB1 but no FB1, water-extracted culture material (WE diet) providing 8 ppm FB1, or untreated culture material (CM diet) providing 71 ppm FB1 for 4 wk. An additional control group was fed a diet containing sound seed corn. Serum chemical and histopathological findings confirmed that the nixtamalized culture material was hepatotoxic and nephrotoxic. Hepatopathy was found in all rats fed the NX or CM diets. The lesions were qualitatively similar in these two groups, but were noticeably less severe in rats fed the NX diet. In contrast, only one rat fed the WE diet exhibited mild hepatopathy. Mild-to-moderate nephropathy resembling that induced by FB1 was found in all rats fed the NX, WE or CM diet. Thus, the organ-specific effects of nixtamalized culture material, containing no detectable FB1, were similar to those of the FB1-containing diet prepared from untreated culture material. Furthermore, nixtamalization was not as effective as water extraction as a detoxification method.