Advances in Food Mycology

198 Marta H. Taniwaki
OA present in the raw coffee. Cleaning and thermal degradation were
the most important factors in the elimination of OA.
Heilmann et al. (1999), studied OA reduction in raw coffee beans
roasted industrially, and showed that levels of OA were significantly
reduced, especially in coffee decaffeinated by solvent extraction. Leoni
et al. (2000) studied 34 samples of ground roasted coffee, 14 instant
coffee and 2 decaffeinated coffee. They found an average of 2.2 µg/kg
of OA in the instant coffee, and in 23 of the ground roasted samples,
values between 0.3 and 6.5 µg/kg of OA were found. When coffee
beverage was prepared from the ground, roasted samples, the OA
content of the resultant coffee was 74 to 86% of that in the original
ground samples.
Urbano et al. (2001a) analysed 18 samples of coffee inoculated with
a strain of Aspergillus ochraceus that produced OA. The samples were
subjected to temperatures of 200˚, 210˚ and 220˚C for 10 to 15 min as
shown in Table 4. The level of OA destruction varied from 22% to 94%
depending on the time and temperature combination. In practice,
however, a treatment of 220˚C for 10 to 15 min may not produce a
sensorially acceptable beverage.
The data in the literature show evidence that the roasting process is
efficient in reducing OA, but there is a lack of more conclusive
research on the effects of the stages of roasting, grinding and beverage
preparation on the stability of the toxin. The effect on OA destruction
of coffee production processes such as roasting, drink
preparation, soluble coffee and decaffeination have been reviewed
elsewhere (Gollucke et al., 2004). It is important that to maintain good
quality coffee, it is advisable to avoid coffee with a high OA content.
Even though roasting or other processes may reduce this toxin, the
quality of the coffee can be affected.
5. OCHRATOXIN A CONSUMPTION FROM
COFFEE
A great deal of interest has been focused on the possible role of
coffee in ochratoxin A consumption. JECFA (2001) has set a
Provisional Tolerable Weekly Intake for OA of 100 ng/kg bw/week
which corresponds to a Provisional Tolerable Daily Intake (PTDI) of
14 ng/kg bw/day. From a survey of coffee drinkers in the United
Kingdom and the data shown in Table 2, Patel et al. (1997) developed
an Estimated Weekly Intake of OA from soluble coffee. Based on