Detecting and controlling mycotoxin contamination of herbs and spices 27
MS) in order to avoid derivatisation. The detection limit was 10 ng and the quantification
limit 25 ng. The advantages of the method can be stated as follows (Ventura et al.,
2004). Using a short column (C18) for chromatographic separation allows rapid
determination obtaining sharp chromatographic peaks and minimising consumption
of the mobile phase. Using low quantities of methanol for the extraction steps avoids
the use of chlorate solvents that are harmful. The polymeric sorbent is as easy to
apply as immunoaffinity columns but is cheaper. Mass spectrofotometric detection is
employed in order to avoid derivatisation which presents several disadvantages.
Mycotoxins are extracted from the food matrix using a suitable solvent mixture.
Mycotoxins such as aflatoxins, ochratoxin A and penicillic acid dissolve in chloroform
better than in a hydrophilic solvent. However, since chloroform is carcinogenic, it
should be replaced by solvents such as methanol:water, acetonitrile:phosphoric acid
or acetic acid, toluene:acetic acid (Ahmed, 2000; Scott, 2002).
For the purification and cleanup steps, commercially available and disposable
SPE columns or cartridges, of which those incorporating silica and immobilised
antibodies for immunoaffinity chromatography are the most widely used (Scott,
2002). A recently introduced technique is the use of molecularly imprinted polymers,
polymers with cavities or imprints complementary in shape to an analyte of interest
(Scott, 2002).
1.4.2 Points to be borne in mind in mycotoxin research
Moulds can cause allergic reactions and some of them are pathogenic. As mould
spores are easily spread in the air, care must be taken while working with them, using
a separate laboratory with restricted entry. As mycotoxins are toxic chemical substances,
care must be taken to avoid exposure to mycotoxins by direct contact and inhalation.
Work must be carried out in a separate laboratory, equipped with a fume hold.
Protective goggles, gloves and lab-coats must be worn. Disposable laboratory wastes
must only be disposed of after they have been soaked in a 10% solution of household
bleach for 30 minutes. In order to remove aflatoxin remnants on glass surfaces, the
articles must be rinsed with methanol, soaked in a 1% solution of household bleach
for two hours, and acetone added to 5% of total volume. They should be left for
30 minutes to react and then washed thoroughly (Trucksess, 2000). As mycotoxin
standards are sensitive to external influences such as light, oxygen and temperature,
a suitable laboratory environment must be ensured.
1.5 Preventing and controlling mycotoxin contamination
Mycotoxins can lead to various diseases in human beings. They also lead to loss of
products and product quality, diseases in animals, low yield generally and reduction
in the number and size of eggs produced. Mycotoxins also seriously threaten the
health of future generations. Aflatoxin B 1 is a human carcinogen (IARC, 1993). As
an etiological agent, it is associated with several human diseases encountered particularly
in Africa, Asia and South America, e.g., primary hepatic carcinoma, hepatic cirrhosis
in children, chronic gastritis, Kwashiorkor and Reye’s syndrome (Ostry et al., 1999).
The products on which most work is being done to bring the mycotoxin hazard
under control are ground nuts, cotton seed and maize. The factors influential in
formation of mycotoxins have been determined with the work carried out so far and