IARC MONOGRAPHS ON THE EVALUATION OF CARCINOGENIC ...

Dietary intake of aflatoxin B 1 was monitored for one week in a number of households
in a Chinese village. Aflatoxin B 1 was detected in 76.7% (23/30) of ground maize
samples (range, 0.4–128.1 μg/kg), 66.7% (20/30) of cooking peanut oil samples (range,
0.1–52.5 μg/L) and 23.3% (7/30) of rice samples (range, 0.3–20 μg/kg) (Wang et al.,
2001).
(a) Co-occurrence of aflatoxins and fumonisins
Co-occurrence of aflatoxin B 1 and fumonisin B 1 in maize and sorghum from Latin
America and Asia is shown in Table 6. Maize harvested in the tropical and subtropical
areas of the world with hot and humid climates is the major commodity contaminated
with the two mycotoxins.
Two studies were carried out on cross-contamination with aflatoxins and fumonisins
in staple maize samples from two high-risk areas for human hepatocellular carcinoma in
China; Haimen, Jiangsu Province, Shandong (Ueno et al., 1997) and Chongzuo County,
Guangxi in 1998 (Li et al., 2001). Three-year (1993–95) surveys demonstrated that
maize harvested in Haimen was highly contaminated with aflatoxins and fumonisins and
that the levels of fumonisins were 10–50-fold higher than in a low-risk area (Ueno et al.,
1997). Staple maize samples from Guangxi were co-contaminated (14/20) with high
levels of aflatoxin B 1 (11–2496 μg/kg) and fumonision B 1 (74–780 μg/kg), and the
probable daily intake was estimated to be 3.68 μg/kg bw of aflatoxin B 1 and 3.02 μg/kg
bw of fumonisin B 1 (Li et al., 2001).
In India, rain-affected maize samples from rural households and retail shops had
higher levels of contamination with fumonisins (250–6470 μg/kg) than normal samples
(50–240 μg/kg) as well as with aflatoxin B 1 (250–25 600 versus 5–87 μg/kg), which cooccurred
with fumonisins. The level of fumonisin B 1 was also higher in sorghum affected
by rain (140–7800 μg/kg versus 70–360 μg/kg). No correlation was observed between
levels of the two toxins in individual samples, indicating that the toxins are formed independently
(Vasanthi & Bhat, 1998).
(b) Occurrence of aflatoxin M 1
Aflatoxin M 1 is a metabolite of aflatoxin B 1 that can occur in milk and milk products
from animals consuming feed contaminated with B aflatoxins (Applebaum et al., 1982).
Data on occurrence of aflatoxin M 1 in milk were summarized earlier (IARC, 1993) and
data reported subsequently are included in Table 7.
Galvano et al. (1996) reviewed the worldwide occurrence of aflatoxin M 1 in milk
and milk products.
1.3.4 Human biological fluids
AFLATOXINS 183
Covalent binding of aflatoxin to albumin in peripheral blood has been measured in a
number of studies (Montesano et al., 1997). The levels of these adducts are assumed to
reflect exposure to aflatoxin over the previous 2–3 months, based on the half-life of