Aflatoxin Contamination Causes Cancer: A Worldwide Evaluation
Posted Jan 20 2010 3:40pm
Mycotoxins are toxins produced by certain moulds or fungi. Although moulds that contaminate foods are usually destroyed by cooking temperatures, the toxins they produce may remain. Aflatoxins are one type of mycotoxin. All naturally occurring aflatoxins are classified as human carcinogens (group 1) by International Agency for Research on Cancer; other mycotoxins, such as fumonisins, are suspected carcinogens. It is common to find co-contamination by more than one species of mycotoxin-producing fungus. In Europe, the joint FAO/WHO expert committee on Food Additives and Contaminants recommends that aflatoxin concentrations in foods be kept as low as possible.
The main foods that may be contaminated by aflatoxins are all types of cereal (grain), including wheat, rice, maize (corn), barley, and oats; and pulses (legumes)-notably peanuts. Nuts and seeds may also be contaminated. Feedstuffs for farm animals may also be contaminated with aflatoxins, which can then be secreted in milk or accumulated in tissues.
Aflatoxins, which are produced by Aspergillus flavus and A. parasiticus, are most problematic in countries with hot, damp climates and poor storage facilities. Under these conditions, food may become contaminated with fungi and then accumulate such toxins. Such foods are marketed and consumed in the countries in which they are produced; they are also exported to neighboring countries and intercontinentally. Aflatoxin contamination is therefore an international issue.
Levels of aflatoxin contamination tend to be highest in countries where rates of liver cancer are high, such as some African countries and South-East Asia, including China. In general, rates are low in Europe, but relatively high rates of contamination have on occasion been found in the USA.Aflatoxin exposure levels are low in Europe and Australia, higher in the USA, and high in many low-income countries. This is particularly the case in tropical and subtropical regions where grains and nuts are stored for long periods under non-ideal conditions.
Rates are reduced by inspection, use of fungicides, and screening of imported foods. However, monitoring of levels of aflatoxin contamination in low-income countries is generally lacking.
References:Reports from International Agency for research on Cancer, Food and Agriculture Organization of the United Nations, World Health Organization, United Nations Environment Program International, Third Joint FAO/WHO/UNEP International Conference on Mycotoxins, World Cancer Research fund and American Institute for Cancer Research.
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