Aflatoxin are naturally occurring mycotoxins that belong to the secondary metabolites produced by many species of Aspergillus flavus, aspergilius parasiticus and aspergillus nomius. Crop (food and feed) which are frequently affected include cereals (maize, sorghum, rice, wheat, barley, job’s tears), oilseed (sunflower, peanut, and other nuts), desiccatted coconut, dried chili, dried shrimps, dried fish, spices, herbs and coffee. The food processed from contaminated raw material is also infected. Aflatoxin can colonize and contaminate crops before harvest or during storage and transportation. Host crops are particularly susceptible to infection by fungi following prolonged exposure to a high humidity environment. The ambient temperature in the range of 28 – 35oC is favorable for Aflatoxin growth. The 4 major naturally occuring aflatoxin are AFB1, AFB2, AFG1 dan AFG2. AFB1 is most frequently found. It is most toxic and carcinogenic to human beings and animals. Exposure to only a small amount of AFB1 is a high risk of liver cancers. There are also aflatoxin M1 and M2, which are the derivatives of the B1 and B2. Milk is can be contaminated with aflatoxins which are resistance to heat up to 280oC. Aflatoxin remain in acidic condition, decomposes in alkaline condition and is slightly soluble. When they enter the body they will be discharged with urine, feces and milk; certain parts of Aflatoxin with turn into metabolites. The most toxic ones are B1, B2 and B3. Chronic exposure also leads to a high risk of developing liver cancers, as the metabolite aflatoxin can intercalate into DNA and RNA and alkylate the bases through its epoxide moiety. At present, aflatoxins are listed by the International Association Research Cancer (IARC) as Class I carcinogens.
Not only are Aflatoxins hazardous to health, they also raise local and international trade issues. For its own benefit, each country sets a limit on each type of Aflatoxin. The Thai Ministry of Public Health Notification No. 98, 1986, imposes a limit of 20 micrograms of Aflatoxin in kg. of food or 20 ppb. Therefore, protective and control measures muse be introduced. The best way of prevention is to avoid the intake of food with Aflatoxin contamination. Aflatoxin are colorless, odorless and tasteless. To find out if the crops are contaminated with Aflatoxins or not, food manufacturer, service provider and consumer must be able to perform fast, efficient and accurate tests. When the tests results are known decision on crops handling can be made in time. The Department of Agriculture specialist have developed the DOA-Aflatoxin ELISA Test Kit through enzyme linked immunosorbent assay (ELISA) technology, using Direct competitive ELISA. This kit is capable of detection of Aflatoxin in samples with 82 -100% accuracy, which is as efficient as the imported ones, but it is much cheaper.
Advantages of DOA-Aflatoxin ELISA Test Kit:
- Samples can easily be collected for tests without any clean up.
- Many samples can be tested simultaneously.
- Tests can be conducted easily, conveniently and safely.
- The analysis is fast: only one hour after sample preparation.
- Highly sensitive. Detection of as low concentration as 0.4 ppb is possible.
- The cost of test per sample is quite high as compared with the chemical method.
- It is non-pollutant; not dangerous chemicals are used.
- Qualitative an quantitative results of the analysis are given.
- Can be used for detection of crops, food and feed.
The kit can be used for testing crops at any stage of food production chain to ensure safety. In the crop processing industries such as food and feed production within the government or private sector, the kit can be used detect Aflatoxins in raw materials prior to food processing or production of feed for animals to ensure that the products are free from contamination, which will help reduce animal deaths or disabilities. Using the kit, the products will meet the standards for local consumption and export. Most important of all, consumers will feel safe because the risk of cancer is reduced; Eating Aflatoxin free food is the way to ensure better health and good living.