Ochratoxin A Overview

Ochratoxins are part of a group of mycotoxins that are secondary byproducts of Aspergillus sp. and Penicillium sp., arising from an isocoumarin structure connected to phenylalanine through an amide bond.

Various forms of ochratoxins exist naturally, including ochratoxin A, ochratoxin B (dechlorinated OTA), and ochratoxin C (ethylated OTA), and are often found together. Ochratoxin A (OTA) is the most prevalent toxin.

Research indicates that this compound can exert various toxic effects such as nephrotoxicity, hepatotoxicity, neurotoxicity, teratogenicity, and immunotoxicity.

Ochratoxin A (OTA) is the most abundant and frequently detected member, also being the most toxic among the three. It is commonly present as a contaminant in a wide range of cereals, vegetables, dried fruits, spices, coffee, fermented beverages, and medicinal plants.

OTA is a weak organic acid with a pKa value of 7.1 and a molar mass of 403.8 g.mol-1. Exhibiting a crystalline structure that can range from colorless to white, this molecule displays intense green fluorescence under UV light in acidic conditions and blue fluorescence in alkaline environments.

Ochratoxin A is a relatively stable molecule and can endure most food processing to some extent, potentially appearing in consumer products.

In the context of wines, OTA is the most extensively researched mycotoxin, and the European Commission (via regulation 1881/2006) has set a maximum tolerable level for OTA in wines intended for human consumption at 2 µg kg−1.

Contamination can occur from the early stages of mycotoxigenic fungi colonization in grapes to the final stages of the wine packaging process.
Ochratoxin A Overview