28 Handbook of herbs and spices
attempts have been made to create control strategies in this respect. However, research
indicates that mycotoxin has still not been brought entirely under control. The most
important factor in arriving at this conclusion is the fact that mycotoxin formation
does not take place in agricultural products such as ground nuts, cotton seed and
maize, in spices such as red pepper and mustard and in dried fruits such as figs only
after they are harvested, it also occurs before they are harvested. The critical stages
after harvesting are drying and storage, but actual contamination takes place before
harvesting, while the product is still ripening. As has been stressed by many researchers,
one of the major factors in aflatoxin formation is the stress period caused by drought
at the end of the season (Dorner et al., 1992; Park, 2002b). Taking this finding as a
starting point, a ‘biocontrol method based on biological competition’ has been developed
(Dorner et al., 1992).
1.5.1 Preharvest controlling
Many types of mould produce mycotoxins which are toxic for human beings, warm-
blooded animals and birds under suitable conditions (Moss, 1998). Although the
presence of mould does not always indicate the presence of mycotoxins, it signals a
mycotoxin hazard. From time to time the presence of mycotoxins in the form of
aflatoxin and ochratoxin is encountered in spices and herbs as well. Incidence of
infection with mycotoxygenic mould is high in physically damaged products which
have been in contact with the soil. Formation of mycotoxin, with certain exceptions,
usually commences at the drying stage following harvesting in red pepper and mustard
(mycotoxin formation has also been observed in these products before harvesting) –
and continues throughout the storage and transportation periods as well. For this
reason it is vital to prevent contact of the product with the soil during harvesting and
drying to avoid mycotoxin formation. Prevention of damage by vermin, insects and
other similar harmful agents, adherence to the rules of hygiene, rapid and effective
drying must also be ensured. Although, following an effective drying process, stability
related to the reduction in water activity is achieved in microbiological terms in
spices and herbs, transportation and storage are other stages which need to be borne
in mind.
Storage conditions, particularly if the product is stored in heaps, encourage the
development of mould. The product can become completely contaminated with mould
and thus be rendered totally unsuitable for consumption. In certain situations, although
development of mould is not observed, mycotoxins may be present in large quantities.
It is for this reason that the practice of storing herbs and spices in heaps should be
abandoned. In addition, it should not be forgotten that mycotoxin control can only be
achieved by means of systematic work among different disciplines. Good agricultural
practices, (GAP), good manufacturing practices (GMP), good hygiene practices (GHP)
and hazard analyses critical control points (HACCP) systems must be implemented.
1.5.2 Technological methods
Work done to bring mycotoxins under control and the latest information on the
methods developed are explained below.
Controlling mycotoxins by microorganisms
Two different strategies can be applied to control mycotoxins in the substrate by