Agriculture Reference
In-Depth Information
8.2.1 Sampling
The collection of representative samples is an important but often underappreciated
phase in the analysis of mycotoxins. Because the distribution of mycotoxins in
agricultural commodities is usually not homogeneous, an incorrect sampling proce-
dure can cause extensive bias when determining the contamination of a particular
commodity [5]. Whereas in the case of liquids it is often assumed that mycotoxins are
evenly distributed, in fungus-contaminated solid samples (e.g., grains, nuts, or dried
fruits) mycotoxins can occur in a few highly contaminated hot spots. The selection of
an optimal strategy that enables proper collection of a representative sample is
dependent on several factors, such as the properties of the sample matrix, type of
packaging, and size of the sampling lot [16]. Sampling and homogeneity of the matrix
become critical and extremely time-demanding, especially with regard to large
samples. If sampling is performed in an improper way, low amounts of sample
(1
5 g) that are being frequently used in rapid sample preparation procedures may
lead to false negative results because local hot spots were missed or undersampled. In
recent years, the design of of
-
cant
concern to many national and international authorities, including the FDA, USDA,
EC, and FAO [19,20]. This effort has resulted in the establishment of sampling
methods that are believed to allow an objective assessment of contamination with
regard to mycotoxins. Worldwide evaluation of these sampling protocols is still in
progress.
cial sampling procedures has become a signi
8.2.2 Matrices of Interest
The studies dealing with monitoring mycotoxins and validating analytical methods
for their determination are typically focused on matrices with the highest incidences
of legislatively regulated compounds. Cereals, nuts, fruits, vegetables, and related
products are in the forefront of interest due to their relatively high susceptibility to
infestation by molds. According to the European Rapid Alert System for Food and
Feed (RASFF), the greatest numbers of alerts are reported for the occurrence of
a
atoxins and OTA in spices, nuts, cereals, and fruits. The presence of these toxins in
named matrices is presumable and under strict control of producers, traders, and
control authorities.
The monitoring studies are also performed for nonregulated compounds to
fill gaps
in knowledge on their occurrence in certain matrices to enable their eventual regulation.
Examples are the lack of incidence data on T2 and HT2 toxins in oats and other cereals
and on OTA in green coffee beans or licorice. The incidence of emergingmycotoxins in
food, feed, and raw materials used for their production is also of signi
cant concern.
Recently, increased attention has been paid to dietary supplements that have gained high
popularity among consumers. Dietary supplement products often contain extracts of
various herbs and botanicals susceptible to fungal attack andmay represent a signi
cant
source of consumers
exposure to mycotoxins [21].
In addition to food, feedstuffs represent an important matrix in the control of
mycotoxins. Signi
'
cant concerns are for silage, because raw materials employed for
