Stability of ochratoxin A (OTA) during processing and decaffeination in commercial roasted coffee beans

Abstract

The fate of ochratoxin A (OTA) during the processing of artificially contaminated green coffee beans, the effect of decaffeination on the production of OTA in green and roasted coffee beans, and the effect of caffeine on the growth and OTA production by Aspergillus ochraceus were studied. The data indicated that the roasting, milling and decoction (brewing and Turkish coffee making) processes caused different percentage reductions in OTA. Decaffeinated samples showed a significantly higher concentration of OTA production than the caffeinated ones. A significantly higher percentage of OTA was reduced when the decaffeination process was performed before roasting treatment. Caffeine at 1.0 and 2.0% concentrations completely prevented OTA production and completely inhibited A. ochraceus growth in YES medium after 3-21 days.

Efficacy of different caffeine concentrations on growth and ochratoxin A production by Aspergillus species

“…Previously, growth and OTA production by a strain of A. ochraceus was completely inhibited by caffeine at 1·0–2·0% on a YES medium after 3–21 days (Nehad et al . ). It may be possible that caffeine content affects the colonization and production of OTA.…”

“…Interestingly, A. steynii was more tolerant while A. ochraceus (ITAL 14) was stimulated to produce higher amounts of OTA at >2% caffeine concentrations. Previously, caffeine concentrations of 1-2% were found to completely inhibit the growth and OTA production by A. ochraceus on a conducive YES medium over 3-21 days incubation (Nehad et al 2005). It appears that a higher caffeine concentration actually inhibits growth and mycotoxin production by some mycotoxigenic species, although there may be some exceptions.…”

“…Some fungal species accumulate lipids, including A. flavus and A. ochraceus as a result of secondary metabolism (Gupta et al 1970;Shin and Marth 1974). Previously, growth and OTA production by a strain of A. ochraceus was completely inhibited by caffeine at 1Á0-2Á0% on a YES medium after 3-21 days (Nehad et al 2005). It may be possible that caffeine content affects the colonization and production of OTA.…”

Occurrence of Ochratoxin A in Coffee: Threads and Solutions—A Mini-Review

“…On contrary, Tsubouchi et al described roasting at 200 • C during 10 and 20 min as an ineffective treatment in the reduction of OTA levels of contaminated coffee beans, since only a decrease of 0-12% was observed [71]. The discrepancy between these findings is difficult to explain but the OTA reduction during roasting may be due to: Epimerization at the C3 position [70,83], thermal degradation with possible involvement of moisture and a physical removal of OTA with chaff [79,83]. In a model system simulating degradation reactions of coffee roasting two products were identified, 14-(R)-ochratoxin A the major compound formed and 14-decarboxy-ochratoxin A at traces levels [24].…”

Ochratoxin A in instant coffee in Italy

“…There is extensive documentation of OTA as a contaminant of coffee, green and roasted coffee beans having been analyzed by many Authors (Aoyama et al, 2010;Batista et al, 2009;Bresch, Urbanek, & Hell, 2000;Coronel, Marin, Cano, Ramos, & Sanchis, 2011;Jørgensen, 1998;Lombaert et al, 2002;Patel, Hazel, Winterton, & Gleadle, 1997;Quintana Guzmán, Antillón Guerrero, & Chaves, 2007;Ramesh & Vasanthi, 2005;Studer-Rohr, Dietrich, Schlatter, & Schlatter, 1995;Terada, Tsubouchi, Yamamoto, Hisada, & Sakabe, 1986;Urbano, Taniwaki, de, Leitao, & Vicentini, 2001;Van der Stegen et al, 1997). The fate of OTA during roasting and decaffeination processes has also been investigated (Blanc, Pittet, Muñoz-Box, & Viani, 1998;La Pera et al, 2008;Micco, Grossi, Miraglia, & Brera, 1989;Nehad, Farag, Kawther, Abdel-Samed, & Naguib, 2005;Romani, Pinnavaia, & Dalla Rosa, 2003).…”