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Mycotoxin
Mycotoxins are toxic metabolites produced by fungus that occurs in food and feed commodities with the capability of causing disease and death among humans and animals. Human food is contaminated by mycotoxins from preharvest to postharvest (along the food chain). Humans are exposed to mycotoxin through consumption of contaminated plant-based foods or carryover of mycotoxins and their metabolites in animal derived products like meat and eggs (Milicevic et al., 2010; Boudra et al., 2007). Mycotoxins subject humans to chronic conditions that can be carcinogenic, mutagenic, teratogenic, estrogenic, estrogenic, hemorrhagic, immunotocxic, and neurotoxic (Milicevic et al., 2010). There are more than 300 known mycotoxins but focus has been on those that are toxic or carcinogenic. Aflatoxin B1 is proven to be the most potent of these and also known to be genotoxic (can damage genetic information and lead to cell mutation that causes cancer). Studies indicate that Aflatoxin B1 accounts for 75% of all contaminations of food plus feed products and is the most widespread among mycotoxin worldwide (Hussein and Brasel, 2001).
How to operationalize the metric
Method of data collection and data needed to compute the method:
The testing of contamination of the food products requires a sample of the food crops or animal product at a given stage of harvest or storage. For aflatoxins, the gold standard measures are the Thin-layer Chromatography (TLC) (de Iongh et al., 1964) and the High Performance Liquid Chromatography (HLPC). The later was developed as an improvement to TLC to ensure an efficient and automated process. These methods are widely used but are expensive and require a long time for preparation of the samples. Therefore, an alternative measure was developed, Immunoassay (Berson et al., 1968). Immunoassay is now used for onsite detention of mycotoxins in food and animal feed (Wacoo et al., 2010). Currently, Enzyme-Linked Immunosorbent Assay (ELISA) (Avrameas, 1969) is widely used in detection of aflatoxin in agricultural food products (Wacoo et al., 2010; Devi et al., 1999).
ELISA-test toolkits, based on immunoassay, are now widely used for onsite tests (Huybrechts, 2011) for mycotoxins for several reasons: 1) the tool kits are inexpensive and easy to use; 2) a large number of samples can be analyzed at the same time; and 3) compared to earlier radio immunoassay, they reduce the health hazards associated with test materials (Twyman, 2005; Wacoo et al. 2010). In recent usage scientists at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) indicated that the use of tool kits from the ELISA family that is, competitive enzyme-linked immunosorbent assay (CELISA), reduced the cost from $25 to $1 per sample (ICRISAT, 2009).
Unit of analysis:
The unit of analysis for this indicator will be toxicity units per gram of agricultural food product.
Limitations regarding estimating and interpreting:
ELISA test kits, although recommended, may still be costly. Therefore, a project needs to ensure that the benefits for testing for mycotoxins are assessed to justify the need for undertaking these measurements. In addition, the use of this technique requires skilled technicians and safety measures to ensure that areas are sanitized and cleaned well after testing.