Contaminants and Foreign Substances


Aflatoxins are toxic metabolites produced by fungus in foods and feeds. Aflatoxins are potentially hazardous if they contaminate the food source. Toxins can cause illness and even death to humans and animals. There are four major aflatoxins: B1, B2, G1, G2.

Aflatoxins are detected in milk, eggs, cheese, corn, peanuts, cottonseed, nuts, almonds, figs, spices, and a variety of other foods and feeds. Highest at risk of aflatoxin contamination are corn, peanuts, and cottonseed.

Aflatoxins can be analyzed by immune-solid phase extraction and HPLC fluorescence methods.

The samples are ground into powder, dissolved in the AOAC suggested solvent, and passed through isolation step (i.e.antibody immune column) and the antibody in the imunocolumn will attract all the aflatoxin and wash out the proteins, sugars or lipids. Then andeluate in sample with very limited collecting solvent. The method is very sensitive and can detect aflatoxin concentrations as low as 5 ppb. The FDA has set maximum limits of aflatoxin as no more than 20 ppb for grain and food, but less than 0.5 ppb for M1 species in milk.

FDA Website for Contaiminents and Pesticides


Fumonisin B1 is the most prevalent toxin, produced by Fusarium molds and found in maize, wheat and other cereals. The FDA/USDA Working Group on Fumonisin advises less than 4 ppm fpr products for human consumption, less than 5 mg/kg in horse feed, less than 10 mg/kg for swine feed, and less than 50 mg/kg for cattle feed. Mycotoxinfumonisins are analyzed by immune-affinity column extraction, HPLC quantitation, and ppb detection limits.


Ochratoxin A, B are mycotoxins produced by Aspergillus ochraceus or Penicillium viridicatum. Ochratoxin A is known to occur in commodities like cereals, coffee, dried fruit and red wine. It is considered a human carcinogen. AOAC approved methods are to test by collecting sample into imnuno-affinity column and analyzing by HPLC. Sensitivity is 0.5 ppb.

Citrinin is a mycotoxin originally isolated from Penicillium citrinum. It has since been found to be produced by a variety of other fungi which are used in the production of human foods such as grain, cheese, sake and red pigments. Citrinin can be analyzed by liquid extraction and imunoaffinity isolation column, and HPLC flourescense and a sensitivity of 10 ppb.


Patulin is a mycotoxin produced by a variety of molds, particularly Aspergillus and Penicillium. It is commonly found in rotting apples. The World Health Organization (WHO) recommends a maximum concentration of 50 µg/L in apple juice. In the European Union, the limit is set to 50 micrograms per kilogram (µg/kg) in both apple juice and cider. The AOAC validated method is by using a mycotoxin isolation column, extracting the petulin in buffer, and separation by HPLC.


Zearalenone (ZEA), also known as RAL and F-2 mycotoxin, is a potent estrogenic metabolite. Zearalenone is the primary toxin causing infertility, abortion or other breeding problems, especially in swine. Higher concentrations (50-100 ppm) can interfere with conception, ovulation, implantation, fetal development, and the viability of newborn animals. Zearalenone is heat-stable and is found worldwide in a number of cereal crops, such as maize, barley, oats, wheat, rice, and sorghum [2] and also in bread. Testing on Zearalenone is based on the AOAC–FDA approved method of imuno-affinity HPLC method. Sensitivity is detected at 0.1 to 5 ppm

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