Aflatoxins are a group of derivatives with similar chemical structures, divided into two categories: B1 and G1, both of which are derivatives of dihydrofuranocoumarin. Aflatoxins are secondary metabolites mainly produced by Aspergillus flavus and A. parasiticus, and the probability of aflatoxins appearing in food and feed in hot and humid regions. They exist in soil, animals, plants, and various nuts, especially grain and oil products such as peanuts, corn, rice, soybeans, and wheat, easily contaminated. Therefore, the food and feed industries’ quality inspection and testing departments will test the aflatoxins in the samples.
How Is Aflatoxin Detected?
Aflatoxin analyzer refers to the detection equipment that uses time-resolved fluorescence quantitative rapid detection of aflatoxin. The aflatoxin analyzer is widely used in immunopathology, microbial antigen, antibody detection, parasitic disease diagnosis, blood disease diagnosis, plant disease, insect research, etc. For the detection of toxins in products, the instrument is simple and convenient, and the detection is fast.
Aflatoxin Detection Method
Chemical Analysis
The most commonly used method is thin-layer chromatography (TLC), which is suitable for detecting grains and their products, condiments, etc., mainly semi-quantitative. Taking advantage of the fluorescence characteristics of AFB1, AFB1 in the sample is extracted and concentrated. After being separated on the thin layer by a one-way or two-way expansion method, blue-violet fluorescence is generated under the irradiation of 365nm ultraviolet light, according to the lowest fluorescence on the thin layer. The detection amount is quantitative, and its sensitivity is 5μg/kg. Since the determination of AFB1 by thin-layer chromatography is not very specific, the interference of other fluorescent substances in the sample causes measurement errors. It can be determined by:
One is to develop a variety of solvent systems, which can separate AFB1, G1, and various AFT analogs;
The second is a chemical test using chromatographic spots, where the sample extract is treated with formic acid thionamide or trifluoroacetic acid, and AFB1 and its analogs are separated by derivatization.
The third is the physical test of chromatographic spots, which can separate non-aflatoxin and AFT according to the difference between ultraviolet absorption spectrum, infrared absorption spectrum, and fluorescent screen spectrum.
Instrumental Analysis
High-performance liquid chromatography (HPLC) is a new chromatography technology developed in the early 1970s, with liquid as the popular phase. It is a good method for the separation and analysis of various AFTs. If equipped with a fluorescence detector, the method has the advantages of high sensitivity, strong separation ability, good specificity, and accurate and reliable measurement results.
It has been widely used in the determination of AFT in food abroad. However, due to the complex composition of food samples, it is necessary to thoroughly and effectively purify the samples before separation and analysis by liquid chromatography. The commonly used purification method is column chromatography, which is cumbersome and requires a lot of organic solvents. As a specific and effective means of separation, purification, and concentration of AFT, the immunoaffinity column has been combined with high-performance liquid chromatography to determine AFT in food, beverage, urine, blood, and milk as soon as it appears. With less organic solvent, sensitivity and accuracy, the entire analysis operation can be completed within 15 minutes.
Immunoassay
Immunoassay uses immunological, enzymatic, and biochemical techniques to open up a new field of AFT analysis. Currently used methods include radioimmunoassay, affinity chromatography, and enzyme-linked immunosorbent assay.
Strong specificity, high sensitivity, relatively accurate and rapid, simple operation, easy to standardize. But there are also serious drawbacks, notably the need for specialized equipment and safety protections, preventing wider adoption.
Using the principle of immunochemical reaction, a large dose of monoclonal antibody is used to adsorb the antigenic substance-AFT in the extract selectively. Because the antigen-antibody reaction has the characteristics of high sensitivity, high selection, and high specificity, the purification effect and detection sensitivity of the sample is greatly improved, and the use of toxic and harmful reagents can be significantly reduced, which is very beneficial to the health and safety of operators. Environmental protection.
Zhang Yibing et al. proposed a new method for detecting AFT by immunoaffinity column purification combined with fluorescence spectrometry, and the detection limit can reach 10-11 ~ 10-12g/ml. Since the 1990s, immunoaffinity technology has been widely used in food analysis. :
Application of Aflatoxin Analyzer in Grain and Oil Production
Generally speaking, if the content of aflatoxin is within the safe limit, it will not pose a risk to consumers’ health. Still, if it exceeds the limit, it will cause acute aflatoxin poisoning. Therefore, to ensure food safety, modern grain and oil production enterprises will use aflatoxin analyzers to carry out safety testing and strictly control the content of aflatoxin in corn, peanuts, and refined oil.
Corn and peanuts are the most common types of food in our lives, and they are also the main raw materials for the production of corn oil and peanut oil. However, corn and peanuts are the two agricultural products with the most serious aflatoxin contamination. The main reason is that the food has been infected by toxin-producing bacteria such as Aspergillus flavus before harvesting. It reproduces and develops under suitable environmental conditions such as temperature and humidity. As a result, toxins are produced, or if they are not sufficiently dried, large amounts of toxins are produced during storage. In addition, edible oil is also very susceptible to aflatoxin contamination, so in agricultural product testing and edible oil production, the application frequency of the aflatoxin analyzer is very high.
The aflatoxin analyzer can quickly and accurately determine aflatoxin content in grain and oil products, preventing unsafe food from entering the market. The aflatoxin analyzer can play an important guiding role in the safe storage of food and the production of edible oil. For example, using an aflatoxin tester to formulate a scientific peanut storage plan, reducing the moisture content to below 9%, so that Aspergillus flavus has no conditions for breeding; or when purchasing peanuts, adopt the method of grading screening and grading storage, and directly screen out the peanuts with substandard quality that contain small grains, incomplete grains, and bacteria-carrying grains, to ensure that peanut products will not contain aflatoxin. It can be seen that the scientific application of an aflatoxin analyzer can keep food away from aflatoxin contamination.
Application of Aflatoxin Tester in Feed Quality
The aflatoxin analyzer can quickly quantitatively measure aflatoxin in feed in a very short period, meeting the work requirements of modern feed quality and safety management.
The feed ingredients most likely to cause aflatoxin contamination are cotton meal, peanut meal, corn, wheat, sunflower meal, soybean meal, and complete feed. Therefore, when purchasing raw materials, enterprises need to use an aflatoxin analyzer to do a good job in the determination of aflatoxin in feed raw materials, to ensure the quality and safety of raw materials, and to ensure the smooth development of subsequent production and processing work and the quality of products produced.
Meet the Target
In addition, during the storage process of feed, if the environment is not up to standard, it will also lead to aflatoxin contamination in feed products. For example, the main factors affecting aflatoxin production in the feed are temperature (over 27°C) and humidity (more than 62%). And the moisture in the feed (more than 14%), etc.
However, studies have shown that the contamination of feed by aflatoxin runs through all aspects of its raw materials, storage, and processing. The degree of pollution depends on the geographical environment, storage, and processing processes. Especially in tropical and subtropical regions, raw materials are more likely to be infected with aflatoxins under high temperature and high humidity environments. Therefore, by making good use of the aflatoxin tester, manufacturers can do a good job in the quality control of products and guide the purchase of raw materials, rational storage and improvement of processing technology, and produce safer high-quality feed products with a more rigorous attitude. Improve the core competitiveness of enterprises.
How Much Is the Aflatoxin Detector
The aflatoxin detector has the advantages of high sensitivity, wide quantitative range, high accuracy, strong stability, and quick and easy operation. It gradually replaces traditional rapid detection products such as colloidal gold test strips and enzyme immunoassay kits. The price of rapid detectors is generally between 2000 to 3000 US dollars.
