Aflatoxins Contamination Analysis

Aflatoxins are toxins that produced by certain kinds of fungi that are naturally found on foods, feeds and agricultural crops.

Figure 1. Chemical structure of aflatoxin B1 and related contaminated foods

Aflatoxins are ubiquitous on a variety types of foods and crops. Four major aflatoxins B1, B2, G1, and G2 as well as two metabolic products M1 and M2 are responsible for the most aflatoxin contamination. Two species of fungi that are mainly associated with the production of aflatoxins of public health significance are Aspergillus flavus and Aspergillus parasiticus. The optimal conditions for the growth of these fungi include high humidity and high temperature. These fungi are typically found on decaying and dead vegetables in tropical and subtropical regions. Other environmental stress such as insect damage, drought stress and poor storage can also contribute to the occurrence of these fungi. The commonly contaminated food crops by aflatoxins include maize, peanuts and tree nuts through pre-harvest contamination. A variety of foods such as rice, coffee and spices can be contaminated by aflatoxins during post-harvest. Then the poor conditions of storage can further increase the contamination level of aflatoxins. Aflatoxins can also cause a significant burden to the economy of the world. It is estimated that annually 25% or more of the world's foods contaminated by aflatoxins were destroyed.

Aflatoxins have been a threat to the health of humans and livestock. Aflatoxins are considered as potent carcinogens and can cause several health consequences with long-term or chronic exposure. They can be harmful to all organ systems especially for the kidneys and liver and can cause liver cancer. Aflatoxins have been shown to be mutagenic and genotoxic in bacteria studies. They have the potential to cause birth defects in children. Aflatoxins can also cause damage to the immune system and may decrease the human's resistance to infectious diseases.

There is a national estimate of dietary exposure to aflatoxins which is generally less than 1 ng/kg body weight per day. The United States Food and Drug Administration (FDA) specified the acceptable levels for aflatoxins in a variety types of human foods and animal feeds. The limits were set as 20 ppb of total aflatoxins for human foods and the acceptable level for milk was 0.5 ppb for aflatoxin M1. The limits were also set as 20 ppb for most animal feeds.

The procedure for the analysis of aflatoxins in foods includes sample preparation and extraction, purification, and detection/quantification. We have expertise in the sample preparation of a variety types of food matrices. The sample preparation has significant effect on the accuracy of the level measured in the food samples.

We offer accurate and validated analytical platforms for both identification and quantification that have been widely applied in the determination of aflatoxins in food samples to meet customers' needs.

Liquid chromatography coupled with mass spectrometry (LC-MS)

LC-MS is a widely used method for the analysis of aflatoxins B1, B2, G1, and G2. This method offers high sensitivity and accuracy.

We also maintain high quality assurance for the analysis. The recovery of internal standard, the use of blanks and spikes is monitored for each batch of analysis.