Ochratoxins Contamination Analysis

Ochratoxins are a family of naturally occurring mycotoxins which are secondary metabolites produced by several fungi of Aspergillus and Penicillium species.

Figure 1. Chemical structure of ochratoxin A and related contaminated foods

There are several types of ochratoxins family, ochratoxin A, ochratoxin B and ochratoxin C and they are usually co-produced. Ochratoxins are weak organic acids which contain a derivative of an isocoumarin. Their chemical structures are slightly different from each other and the structure determines their potential toxic effects. Among them, ochratoxin A (OTA) is the most prevalent and toxic ochratoxin and most commonly detected in foodstuffs. Ochratoxin A can contaminate a variety of foods and agricultural crops such as cereal and cereal products. It has been also associated with other food commodities including beer, coffee, and dried fruits. The crops can be infected by the fungi during growth in the field and during harvest and storage. The optimal conditions of the fungi growth are moist and mild temperature environment. Ochratoxin A may still present in the foodstuffs even the visible mold of the mycotoxin is not seen. It is relatively stable and can survive during the food cooking process. The levels of ochratoxins in the foods are closely related to the environment of growth and processing.

Ochratoxin A is toxic and potentially carcinogenic to human health. The potent toxic effect of ochratoxin A is mainly on the kidney and it can lead to the pathological changes in the kidney. The greatest health impacts of ochratoxin A are subchronic and chronic effects. Ochratoxin A can cause neurotoxic, immunosuppressive and genotoxic effects on humans and animals. It is also reported to cause hepatic damage in animal studies.

The Joint FAO/WHO Expert Committee on Food Additives (JECFA) has established a provisional tolerable weekly intake for ochratoxin A as 100 ng/kg body weight per week. The European Commission has specified the maximum levels for ochratoxin in a variety types of foodstuffs. The contamination limits ranged from 0.5 µg/kg for processed cereal-based foods for infant foods and young children, 5 µg/kg for raw cereal grains and roasted coffee beans, to 10 µg/kg for dried vine fruits and soluble coffee.

The procedure for the analysis of ochratoxins in foods and animal feeds includes sample preparation and extraction, purification, and detection/quantification. Liquid extraction using an organic solvent in the presence of acid was performed to extract the mycotoxins from foodstuffs. 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 the identification and quantification that have been widely applied in the determination of ochratoxins in food and animal feed samples to meet customers' needs.

Liquid chromatography coupled with mass spectrometry (LC-MS)

LC-MS is a widely used laboratory based method for the analysis of ochratoxins. The method offers low limit of detection and high 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.