Ochratoxin A in Roasted Coffee from French Supermarkets and Transfer in Coffee Beverages: Comparison of Analysis Methods

Abstract

The OTA content of 30 roasted coffees purchased in French supermarkets was evaluated by two validated different methods: one using immunoaffinity column (IAC) clean-up after alkaline extraction; the second using toluene extraction under acidic conditions. OTA recoveries (0.5 to 5 µg/kg) ranged from 16–49% with the alkaline extraction method and 55–60% with the acidic method. OTA recoveries from prepared beverages were similar with all methods (75–80%). All samples containing OTA ranged from trace (<LOQ) to 11.9 µg/kg. About 20 to 140% of OTA passed through the beverages. Recoveries of over 100% of OTA in beverages were due to three types of interferences: (i) formation of open-ring OTA (OP-OA) during alkaline extraction, (ii) isomerization of OTA during roasting, and (iii) presence of the nonchlorinated analogue OTB. The first two types of interference generate OTA derivatives that are not recognized by OTA antibodies, while OTB cross-reacts with OTA-antibodies. These analytical problems will seriously impact the amount of OTA detected, especially at the levels close to the limits from the EU legislation. Underestimation of OTA could be highly dangerous for health.

Overview on the mechanisms of coffee germination and fermentation and their significance for coffee and coffee beverage quality

“…Far lower levels have been reported in other studies; 20-80 µg/kg -1 (Levi et al, 1974), 0.2-15 µg/kg -1 (Micco et al, 1989), 0.1-48 µg/kg -1 (Romani et al, 2000), a maximum of 1.8 µg/kg -1 in severely infected coffee beans from Vietnam (Leong et al, 2007) and 0.5-11.9 µg/kg -1 was recently reported in roasted coffee available in the French market (Tozlovanu and Pfohl-Leszkowicz, 2010 (Batista et al, 2003).…”

Detection of ochratoxin A (OTA) in coffee using chemiluminescence resonance energy transfer (CRET) aptasensor

“…In generally, it is significantly difficult to determine hazards including OTA in coffee due to interfering brown-colored substances and matrix effects (Tozlovanu & Pfohl-Leszkowicz, 2010). We investigated that the activity of HRPzyme depended on the volume of extracted coffee (2-fold dilution with deionized water after extraction) without OTA, and the chemiluminescence signal decreased with increasing coffee volume (Fig.…”

“…Extraction of roasted coffee beans was based on an EU-validated method with modifications (Tozlovanu & Pfohl-Leszkowicz, 2010). Roasted coffee beans were ground by a blender for 5 min.…”

“…Since the detection of OTA in coffee is difficult due to the interference of brown-colored substances and UV-Vis absorption qualities (Tozlovanu & Pfohl-Leszkowicz, 2010), we have designed a homogeneous CRET aptasensor platform for OTA detection in coffee through the quenching of chemiluminescence signals. We validated our CRET aptasensor in a previous study (Mun et al, 2014).…”

Semi-automated solid-phase extraction method for studying the biodegradation of ochratoxin A by human intestinal microbiota

“…However they present several drawbacks: manual SPE is tedious and time-consuming, entailing personal costs; immunoaffinity columns are quite expensive, not reusable and present limited lifetime. In addition, OTB was found to interfere with OTA antibodies on immunoaffinity columns [19]. Consequently we found interesting to develop a rapid and simple semi-automated SPE method, using common C18-silica cartridges, in order to offer a rapid and cheap method to be used for monitoring OTA biodegradation; such reversed-phase cartridges were reported to be efficient for the analysis of OTA in aqueous beverages (wine, beer) [20][21][22][23].…”