Detecting and controlling mycotoxin contamination of herbs and spices 5
ochratoxin in tropical climates (Heenan et al., 1998; Pitt, 2002). The maximum
temperature for the growth of A. carbonarius is approximately 40 ∞C, whereas the
optimum temperature 32–35 ∞C (WHO/FAO, 2001). Deoxynivalenol is produced
under conditions of low oxygen tension. In growing crops, DON is not found (Miller
et al., 1983). In contrast, zearalenone requires oxygen saturation for optimal production,
a condition seen after field crop senescence (Miller, 2002).
The optimum temperature for aflatoxin production is 25–30 ∞C and the maximum
is 48 ∞C. The higher temperatures and drought conditions also may favour A. flavus
over other fungi because of its ability to grow on substrates with low water activity
(CAST; 2003). These conditions should be present simultaneously; the presence of
only one is not sufficient (Payne, 1998). Researchers found that peanuts grown with
adequate moisture did not contain aflatoxin. Similarly, peanuts grown under prolonged
drought with temperatures less than 25 ∞C or greater than 32 ∞C were free of aflatoxin.
Colonisation by A. flavus and aflatoxin contamination maximised at 30.5 ∞C (CAST,
2003). In addition to the production of aflatoxin before harvesting, the adverse conditions
during drying, transporting and storing cause accumulation of higher amounts of
aflatoxin. Aflatoxin synthesis starts after 24 hours depending on the conditions and
reaches its maximum level between 36–60 hours (Cary et al., 2000).
Mycotoxins found in spices and herbs and the analysis method used are presented
in Table 1.1. As seen from the table, among spices and herbs the most frequently
studied spice is red pepper and the most frequently encountered mycotoxins are
aflatoxin and ochratoxin. Several mycotoxins were detected in spices and herbs such
as aflatoxin, fumonisin, ochratoxin A, mycophenolic acid, penitrem A, zearalenone
and trichothecenes.
1.2.1 Red pepper
Mycotoxins and their maximum levels detected in red pepper were 969 mg/kg AFB 1
(Reddy et al., 2001), 50.4 mg/kg OTA, 15.4 mg/kg ZEN, and 81 mg/kg trichothecenes
(Patel et al., 1996). Aflatoxin can be produced before and after harvest in red pepper.
Taydaş and Aşkın (1995) determined AFB 1 with maximum concentration 1.45 mg/kg
in three of 33 red pepper pod samples, collected from fields before harvest. Reddy et
al., (2001) studied 124 samples of three different qualities of chili pods and found
that aflatoxin contamination could be correlated with sample grades such as 50% in
grade 1, 66% in grade 2, 93% in grade 3. The highest concentration of 969 mg/kg
AFB 1 was found in one sample representing grade 3 (low quality).
Heperkan and Ermiş (2004) studied 36 ground (flakes) red pepper samples obtained
from different producers from four regions in Turkey. Aflatoxin B 1 was detected in
five samples (14%) at levels between 10.5–31.2 mg/kg. The amount of toxin was
higher but the incidence was lower than that noted by other researchers (Taydaş and
Aşkın, 1995) who studied similar areas in Turkey. AFB 2 (El-Dessouki, 1992) and
AFG 1 (El-Dessouki, 1992; Dokuzlu, 2001) were also detected in addition to AFB 1 , in
red pepper.
The amount of aflatoxin in red pepper listed in Table 1.1 was higher than the limits
of EC standards (2 mg/kg) except for one study. Low levels of aflatoxin B 1 (0.8 mg/
kg) were found in one of two red pepper samples (Taguchi et al., 1995). In addition
to aflatoxins and ochratoxin A, other mycotoxins such as fumonisin, zearalenone and
trichothecenes (Patel et al., 1996) were also determined in red pepper.