Challenges on Production of a Certified Reference Material of Ochratoxin A in Roasted Coffee: A Brazilian Experience

• Published in: Journal of AOAC International Vol. 102; no. 6; pp. 1725 - 1731
• Main Authors: do Rego, Eliane C P, Leal, Rodrigo V P, Bandeira, Raquel D C C, da Silva, Michelle R, Campos, Erika G, Petronilho, Caroline F, Rodrigues, Janaína M
• Format: Journal Article
• Language: English
• Published: England AOAC International 01-11-2019
• Subjects: Analysis; Brazil; Carbon Isotopes; Chromatography, Affinity - methods; Coffee - chemistry; Customer relationship management software; Feasibility Studies; Food Contamination - analysis; Indicator Dilution Techniques; Ochratoxins - analysis; Ochratoxins - standards; Reference Standards; Brazil
• ISSN: 1060-3271; 1944-7922
• DOI: 10.5740/jaoacint.19-0045

Coffee is an important agricultural commodity with technical barriers for exportation because of possible contamination with ochratoxin A (OTA), a mycotoxin nephrotoxic and carcinogenic. The maximum limit for OTA in roasted coffee is 5.0 μg/kg in the European Union and 10 μg/kg in Brazil, and the use of certified reference materials (CRM) is required for reliable measurements.
This paper describes the development of a candidate CRM of OTA in roasted coffee following the requirements of ISO 17034 and ISO Guide 35.
A primary method of isotope dilution MS was developed and validated using (
C
)-OTA as internal standard. The sample preparation was based on AOAC
using immunoaffinity column.
The linear working range is 2.0-15.0 μg/kg, with recoveries of 92.2-110.8% and relative SDs lower than 12.4%. The method was successfully applied to the feasibility study, which defined the procedure for preparation of a large batch around 5 μg/kg. It was produced by spiking blank roasted coffee with OTA standard, mixing and filling in amber flasks with 50 g of coffee, and storing at -80°C. The homogeneity study showed an acceptable degree of heterogeneity of 1.44%, and the short-term-stability study defined the conditions for transportation as maximum temperature of 50°C up to 28 days.
These results show that certification is possible.
The long-term stability study at -20°C is in progress, and the characterization will be conduzed by a interlaboratory comparison. This material will be an important tool for QC in laboratories.