Chemical detection of Aflatoxins in dairy products
High performance liquid chromatography
High performance liquid chromatography (HPLC) is a widely used analytical technique. It allows samples to be separated and their components determined.
The basic principle of HPLC is passing a sample through a column packed with tiny particles (usually less than 10um diameter) and applying high pressure to increase the resolution and speed of the technique.
There is solvent constantly flowing through the system. This solvent is called mobile phase. To ensure the solvent is constantly moving through the system a pump is employed. This gives the required pressure to allow mobile phase and sample to move through the column with ease and speed. 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. If an unknown sample is then injected and peak obtained at the same retention time.
The peak area can be used to calculate the amount of standard material in the unknown by proportion.
HPLC is especially important for evaluation of non-volatile compounds, providing rapid determination of additives, contaminants and natural components of food products.
Mycotoxins present in food products
Mycotoxins are substances created by fungal secondary metabolic processes which are in connection with specific disorders in animals and humans. The action of toxicity in animals is as harmful as the fungal species which produce these compounds.
Aflatoxins in milk products
A notable example of mycotoxins is aflatoxin that usually brings about liver damage and cancer, reducing the milk production and inhibiting immune system.
Aflatoxin M1, is a toxin found in milk extracted from ingested aflatoxin. Identification of M1 is important since it is likely to be found in milk which is an essential source of nutrition for human.
There are significant regulations (throughout the world) concerning the presence of aflatoxin M1 in dairy products.
Afla M1 HPLC is a rapid aflatoxin test from which accurate numerical results can be achieved. Using monoclonal affinity chromatography, Afla M1 can isolate aflatoxin M1 from dairy products.
Aflaprep M test
Aflaprep M is a technique grounded on monoclonal technology that has been reported to be 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 process is the immunoaffinity column which is provided with a gel suspension of monoclonal antibodies (anti-aflatoxin M1) that are covalently bound to a solid support.
Basically the milk samples are filtered and passed through the column and any potentially 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 bound is then discharged by the antibody as a result of elution from the column with methanol /acetonitrile. The content of aflatoxin M1 is measured by reverse phase HPLC connected to a fluorescent detector.
Discussion
Most mycotoxins are usually determined by thin-layer chromatography (TLC), but higher separation power and less time consuming analysis of HPLC are probably the main reasons for using this technique to a greater extent (rather than the other chromatography methods).
With regard to aflatoxin M1 analysis in milk products, the typical test of Aflaprep M is probably more extensively used than traditional clean-up methods since highly specific, sensitive and quick results can be obtained in addition to providing simple procedures to carry out.
In conclusion:
Aflatoxin unavoidably occurs on certain food products. However adequate quality control procedures can be followed by food and feed companies in order to satisfy legal standards and ensure consumer safety.
Mycotoxin analysis by HPLC is safe and simple.
The experiment can be quickly performed by unskilled personnel.
It is a simple test with feasibility of obtaining accurate results with high sensitivity (speed – quick tests for parts per billion or per trillion can be obtained).
