stringent legislative or guideline levels, some of the more recent of which
are shown in Table 8.3.
It is now realized that aflatoxins are not simply a problem of poor
storage, but they can be produced in the growing crop before harvest.
Aflatoxigenic species ofAspergilluscan establish an endophytic relation-
ship with the healthy plant and produce low, but significant, amounts of
aflatoxin when the plant is stressed, such as occurs during a drought.
Like many microbial secondary metabolites, the aflatoxins are a
family of closely related compounds, the most toxic of which is referred
to as aflatoxin B1 (Figure 8.9). The precise nature of the response to
aflatoxin is dependent on species, sex and age, in general the male is more
sensitive than the female. Some animals, such as the day-old duckling
and the adult dog, are remarkably sensitive to the acute toxicity of
aflatoxin B1 with LD 50 values of 0.35 and 0.5 mg kg^1 body weight
respectively, while others, such as the adult rat and the mouse, are more
resistant (LD 50 ca.9mgkg^1 ). Not all animals respond to the carcino-
genic activity of aflatoxin but for the rat and the rainbow trout aflatoxin
B1 is one of the most carcinogenic compounds known.
Table 8.3 Some maximum tolerated levelsafor aflatoxin in foodstuffs
Country Commodity Tolerance(mgkg^1 )
Australia Peanut products 15
Belgium All foods 5
Canada Nuts and nut products 15
China Rice and other cereals 10
France All foods 10
Infant foods 1
India All foods 30
United Kingdom Nuts and nut products 2 a
United States All Foods 20
aOn 16 July 1998 the European Commission set maximum tolerated levels for a number of food
commodities (EC Regulation 1525/98 EC) and Member States were allowed a period of time to
comply. UK Statutory Instrument, Contaminants in Food (Amendment) Regulations 1999 (SI No.
1999/1603) came into force on 30 June 1999 reflecting UK compliance with the EC regulation
Figure 8.9 Aflatoxin B1
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