Agriculture Reference
In-Depth Information
allows ready adoption of analytical methods to technical developments and a faster
answer to newly emerging problems. Instead of using standardized methods, the
EU is focused on describing performance characteristics, limits, and criteria that
have to be ful
lled by the applied methods.
Finally, it is important to indicate that Codex Alimentarius has also established
performance criteria for analytical methods for veterinary drugs (CAC/GL 71
-
2009) [40] and they will be established for marine toxins and pesticides in the
near future.
6.3 ANALYTICAL TECHNIQUES FOR VD RESIDUE ANALYSIS
As aforementioned, the presence of VD residues and their associated harmful effects
on humans make their control an important issue in ensuring consumer protection.
Analytical methods used to monitor VDs in feed and food are essential to ensure
human and animal health, monitor consumer exposure, reduce the impact of
chemicals on the environment, support the enforcement of laws and regulations,
and facilitate international trade of animal food products. However, the development
of these methods is a dif
is
complex and covers several classes of chemical compounds that exhibit many
different chemical properties. Among these different classes of compounds, two
relevant groups are antimicrobial medicines (e.g., antibiotics or dyes) and drugs
exhibiting growth-promoting properties (e.g., steroids,
cult task because the generic term
“
veterinary drugs
”
-agonists, thyrostats, or
growth hormones). In addition, these compounds can be present in a wide variety
of complex foodstuff samples.
Basically, analytical methods can be classi
β
ed into two main groups: screening
methods and con
first to determine the
absence/presence of an analyte or a group of analytes at the concentration of interest.
These types of methods provide a qualitative binary response and samples are
classi
rmatory methods. Screening methods are used
ed as negative or nonnegative. Afterward, nonnegative samples must be
analyzed by a con
cation method to determine the concentration
of the target analyte(s) in those samples. This strategy is suitable to reduce the number
of samples to be quantitatively analyzed, and it can be applied in routine laboratory
analysis with high throughput.
Traditionally, VD residues in food samples have been detected by microbiological
or immunochemical techniques, which provide a rapid detection of certain com-
pounds [41,42]; for instance, in many areas, rapid milk testing for antimicrobials were
used. However, several drawbacks related to the lack of selectivity and the inability of
providing quantitative determination (requiring another technique for that purpose)
have led them to be replaced by physicochemical techniques. In this way, the
combination of MS with gas chromatography (GC) or LC is extensively used in
the simultaneous identi
rmation/quanti
cation of VD residues in feed and
food [43,44]. Nowadays, analytical strategies to determine VDs are predominantly
based on LC
cation and quanti
MS due to its applicability for direct determination of polar compounds,
such as most VDs; other less polar compounds are also LC amenable after appropriate
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