Chemical detection of Aflatoxins in dairy products
Aflatoxins refer to the naturally occurring mycotoxins. They are responsible for specific disorders in animals and humans including liver cancer, reduction of the milk production and suppression of the immune function. Aflatoxin M1, is a toxin found in milk that is liberated in the body after the ingestion. Identification of Aflatoxin M1 is important since it is likely to be found in the milk which is an essential source of nutrition for human.
There are specific regulations concerning the presence of aflatoxin M1 in dairy products.
Afla M1 HPLC (High performance liquid chromatography) is a rapid aflatoxin test from which accurate numerical results can be achieved. The principle of this method is based on transferring the sample through a column (packed with tiny particles) which is subjected to a high pressure in order to increase resolution and speed. The solvent; namely mobile phase, constantly flows through the system. The sample is injected into the mobile phase so it can proceed directly to the column. The sample comes out from the column (elutes) and proceeds to the detector. This monitors the refractive index difference between the pure mobile phase entering the column and the column elute. The signal from the detector is sent to a data recorder. This measures the time of each component (retention time) and the size of the signal (peak area). By injecting a known standard a retention time and peak area are achieved. HPLC is especially important for evaluation of non-volatile compounds. It provides rapid determination of additives, contaminants and natural components of food products.
Aflaprep M is also an analytical technique that involves monoclonal technology. This method is more effective than traditional clean-up procedures. The test is highly specific, sensitive, fast and easy to conduct with feasibility of high extent screening. The main component of the Aflaprep M is the immunoaffinity column with a gel suspension of monoclonal antibodies (anti-aflatoxin M1) that are covalently bound to a solid support. The milk samples are filtered and passed through the column. The present aflatoxin M1 is captured by the antibody through the gel suspension. The column is then washed with water to remove undesired non-specific materials. The toxin portion is then expelled as a result of elution from the column with methanol or acetonitrile. The content of aflatoxin M1 is measured by the reverse phase HPLC connected to a fluorescent detector.
Most mycotoxins can be determined by thin-layer chromatography (TLC). HPLC is more commonly used technique due to its higher separation power and less time consuming analysis. Aflatoxin unavoidably occurs on certain food products. In this regard, adequate quality control is essential to be followed by the food/feed companies in order to comply with the legal standards and ensure the consumer safety.