presence of aflatoxins in smoked-dried fish sold in abeokuta, ogun ...

2.10 Cases–Control Studies
Olubuyide et al. (1993) carried out a small case–control study in Nigeria to assess the role of
HBV and aflatoxins in primary hepatocellular carcinoma. Cases were 22 patients at a university
hospital in Ibadan in 1988. Controls were 22 patients from the gastroenterology ward of the same
hospital with acid peptic disease unrelated to liver diseases and matched to cases for sex and age.
Blood samples were collected after subjects were on hospital diet for one week and were
analysed for HBsAg and a number of aflatoxins (B1, B2, M1, M2, G1, G2) and aflatoxicol.
HBsAg was detected in 16 cases and 8 controls. Elevated levels of aflatoxins were detected in
five (23%) cases and one (5%) control, the difference being significant (p < 0.05).
2.11 Analysis of Aflatoxin in Foods
Methods for determining aflatoxins in agricultural commodities and food products have been
verified by AOAC International (Stroka et al., 2001) and by various international committees
(ISO, 2001). The methods have greatly improved in recent years with the commercial
availability of multifunctional columns and immunoaffinity columns, which are simple and rapid
to use, and with reduction in the use of toxic solvents for extraction and clean-up.
A number of approaches have been used to analyse aflatoxins and their metabolites in human
tissues and body fluids. These include immunoaffinity purification, immunoassay (Wild et al.,
1987), high performance liquid chromatography (HPLC) with fluorescence or ultraviolet
detection and synchronous fluorescence spectroscopy (Groopman et al., 1991). Molecular
biomarkers, such as urinary markers, metabolites in milk and parent compounds in blood, are
used for determining exposure to aflatoxins (Groopman, 1993).
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