- Solvent residues
- Plasticisers
- Process Chemicals
- Contaminated raw materials
- Contaminated water
- Thermal degradation products
- Chemical degradation products
- Microbiological metabolites
In its simplest form, tainting occurs by contamination
of the food with a single chemical compound
from a single source (eg solvent vapours from
printing inks on the packaging). These cases
are relatively easy to solve. However, in some
cases the source of taint appears nebulous because
the taint compound was formed by a series of
chemical reactions involving non-tainting chemicals
from a variety of sources. In these cases the
taint compound cannot be attributed to a single
source and the investigator needs to determine
the sources of the precursor compounds and to
establish the chain of events which led to the
formation of the taint compound.
Mechanisms for Taint Migration
Food will only become tainted if the taint compound
is actually present in the food. The mechanism
by which the taint compound (or in some cases
its precursor) moves into the food is called
migration. There are many forms of migration,
some of which are listed below. The variety
of chemical and physical properties of tainting
compounds means that some compounds have preferred
migration routes, and conversely some taints
can be prevented by blocking the migration mechanism.
However, the preferred method of taint resolution
will always be the elimination of the taint
compound at its source.
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