AFLATOXINS
- Found in cereal, oilseeds, spices, tree nuts and milk.
- Members of aflatoxins found in our pdt are B1, B2, G1, G2, M1
- Legal limits
• B1 cannot exceed 2 parts per billion
• B1+B2+G1+G2 cannot exceed 4 parts per billion
• M1 cannot exceed 0.5 parts per billion
• Total aflatoxins in foods has to be less than 20 ppb
- Methods of Analysis:
• Solid-Phase Extraction
There are three steps involved in all analytical methods: extraction, purification, and determination. The solid-phase extraction is the purification step.
Test extracts are cleaned up before instrumental analysis to remove coextracted materials that often interfere with the determination of target analytes.
• Thin-Layer Chromatography
* most widely used separation techniques
* it has been considered the AOAC official method and the method of choice to identify and quantitate aflatoxins at levels as low as 1 ng/g.
• Liquid Chromatography
* similar to TLC in many respects
* use TLC for preliminary work to optimize LC separation conditions
* normal-phase LC (NPLC), reversed-phase LC (RPLC) with pre- or before-column derivatization (BCD), RPLC followed by postcolumn derivatization (PCD), and RPLC with electrochemical detection.
• Immunochemical Methods
* identify and measure aflatoxins in food in less than 10 minutes
* radioimmunoassay (RIA), enzyme-linked immunosorbent assay (ELISA), and immunoaffinity column assay (ICA)
* Thin layer chromatography and LC methods
> Laborious and time consuming
> require knowledge and experience of chromatographic techniques to solve separation and interference problems
• Confirmation of Identities of the Aflatoxins:
* Chemical derivatization
* mass spectrometry (MS)
- Aflatoxins and Human Health• difficult to avoid because fungal growth in foods is not easy to prevent
• though heavily contaminated food supplies are not permitted in the market, concern still remains for the possible adverse effects resulting from long-term exposure to low levels of aflatoxins in the food supply.
• Can cause occurrence of acute aflatoxicosis
• Conditions increasing the likelihood of acute aflatoxicosis in humans include limited availability of food, environmental conditions that favor fungal development in crops and commodities, and lack of regulatory systems for aflatoxin monitoring and control.
References
http://www.commercialdiplomacy.org/case_study/egyption_peanuts.htmhttp://www.ansci.cornell.edu/plants/toxicagents/aflatoxin/aflatoxin.html#Aflatoxins
Applied Food Science And Nutrition.
8:00 PM
