Occurrence of the Ochratoxin A Degradation Product 2'R-Ochratoxin A in Coffee and Other Food: An Update.

Franziska Sueck,Jonas Specht,Hans-Ulrich Humpf,Olga Torres,Vanessa Hemp,Benedikt Cramer

doi:10.3390/toxins11060329

Franziska Sueck, Jonas Specht + Show 4 more

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https://doi.org/10.3390/toxins11060329

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Abstract

Food raw materials can contain the mycotoxin ochratoxin A (OTA). Thermal processing of these materials may result in decreased OTA levels but also in the formation of the thermal isomerization product 2′R-ochratoxin A (2′R-OTA). So far, only 2′R-OTA levels reported from 15 coffee samples in 2008 are known, which is little when compared to the importance of coffee as a food and trading good. Herein, we present results from a set of model experiments studying the effect of temperatures between 120 °C and 270 °C on the isomerization of OTA to 2′R-OTA. It is shown that isomerization of OTA starts at temperatures as low as 120 °C. At 210 °C and above, the formation of 25% 2′R-OTA is observed in less than one minute. Furthermore, 51 coffee samples from France, Germany, and Guatemala were analyzed by HPLC-MS/MS for the presence of OTA and 2′R-OTA. OTA was quantified in 96% of the samples, while 2′R-OTA was quantifiable in 35% of the samples. The highest OTA and 2′R-OTA levels of 28.4 µg/kg and 3.9 µg/kg, respectively, were detected in coffee from Guatemala. The OTA:2′R-OTA ratio in the samples ranged between 2.5:1 and 10:1 and was on average 5.5:1. Besides coffee, 2′R-OTA was also for the first time detected in a bread sample and malt coffee powder.

Highlights

The mycotoxin ochratoxin A (OTA, Figure 1) can be found in a broad spectrum of food raw materials infested with fungi of the genera Aspergillus and Penicillium as well as in food products derived from these commodities [1]
The The isomerization of OTA to 20 R-OTA as well as the formation of other degradation products were isomerization of OTA to 2′R-ochratoxin A (2′R-OTA) as well as the formation of other degradation products studied model in heating
The thermal instability of the mycotoxin OTA has been reported for several food processing technologies

Summary

Introduction

The mycotoxin ochratoxin A (OTA, Figure 1) can be found in a broad spectrum of food raw materials infested with fungi of the genera Aspergillus and Penicillium as well as in food products derived from these commodities [1]. Considering exposure within the European Union, cereals and cereal products, such as pasta, bread, and beer, are the most relevant OTA sources due to the high consumption rates of these food items. Approximately 12% of the total OTA exposure occurs from coffee drinking and a further 6% from cocoa, 6% from meat, and 5% from wine [1]. A quantitative analysis of 15 coffee samples from the German market indicated that DC-OTA is only Toxins 2019, 11, 329; doi:10.3390/toxins11060329 www.mdpi.com/journal/toxins coffee roasting lead to a decarboxylation to form decarboxy-ochratoxin A (DC-OTA) as well as to racemization of the phenylalanine moiety to yield 2′R-ochratoxin A (2′R-OTA, previously reported as 14(R)-OTA) and to the formation of ochratoxin α-amide (OTamide) as shown in Figure 1 [20,21,22].

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