Detecting and controlling mycotoxin contamination of herbs and spices 3
1.1 Introduction
Spices have been used in foods, mainly as flavouring and colouring agents as well as
for their functional properties such as being antioxidant and antimicrobial. While
some spices inhibit growth of microorganisms and some retard their growth others
reduce mycotoxin production (Bullerman et al., 1977; Akgül and Kıvanç, 1998; Yin
and Cheng, 1998; Beuchat, 2001; Juglal et al., 2002). They can be invaded by
bacteria, yeast and moulds themselves immediately after harvesting till final consumption
(Schwab et al.,1982; Garrido et al.,1992; McKee, 1995; Erdogrul, 2000; Garcia et
al., 2001). Mycotoxins are toxic metabolites produced by different genera of moulds
under favourable conditions. Moulds can contaminate agricultural commodities during
harvesting, drying, processing and storage and some of them are capable of producing
secondary metabolites, causing acute or chronic diseases in human and animals.
Mycotoxins can also be found in animals and animal products through the ingestion
of mouldy feed.
There are approximately two secondary metabolites per fungal species which
means that there are potentially 20,000 to 300,000 unique mycotoxins (CAST, 2003).
Among these mycotoxins, the ones that have world-wide importance and are currently
considered are aflatoxins, deoxynivalenol, fumonisins, ochratoxin A, T-2 toxin and
zearalenone (WHO/FAO, 2001). This evaluation has been based on significant impact
on human health and animal productivity (WHO/FAO, 2001), however, the emphasis
can vary from country to country or among regions, altering the ranking. For example,
fumonisin presence in corn is not considered to be an important hazard in Australia,
because corn is not a frequent item in the diet (Pitt and Hocking, 2004). On the other
hand, fumonisin in corn is considered to be among the primary important mycotoxins
in the USA (Miller, 2002). Similarly, aflatoxin does not pose an important threat to
consumers in Europe, since it does not appear in high concentrations due to inconvenient
temperatures, and moreover the limits are extremely low and inspections are strict on
imported products. It keeps its importance in countries where the temperature is
convenient, such as in the USA (Bhatnagar et al., 2004), Africa (Shephard, 2004;
Njapau and Park, 2005), and Asia (Park et al., 2005).
1
Detecting and controlling mycotoxin
contamination of herbs and spices
D. Heperkan, Istanbul Technical University, Turkey