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Sampling. Until quite recently a non-volatile
insecticidal spray applied to fruit could be relied upon
to leave a visible residue when it dried. Many of the
newer insecticides, however, might leave little or no
residue when applied to fruit or vegetables, and this
makes the job of the sampling officer, whether at the
port or in the market, extremely difficult.
Analysis. Small, but possibly toxic, proportions of
many of the new pesticides would escape detection in
fruit and vegetable products in a general analysis of the
kind hitherto carried out for the purposes of the Pood and
Drugs Act. Although methods for the analysis of residues
of some of the new pesticides have been worked out, these
are complex and present a number of technical difficulties,
partly because of the many insecticides now used.
Enforcement. Although the toxicity of some of the
new organic pesticides would appear to be as high as
that of the most poisonous of the older inorganic insecticides,
no safe limits for their residues in food have
been laid down, nor even suggested, by either of the
Ministries concerned, for the use of local authorities.
In the absence of official limits it would be difficult
to establish in a Court of Law that a residual trace of
an insecticide was injurious to health. Even if a
sampling officer happened to procure a sample of contaminated
produce, and the analyst to detect the contaminant,
the local authority might still be in no
position to assess the danger, if any, nor to take
suitable action.
Dr. Amphlett Williams states that consideration of
these problems leads inevitably to the conclusion that
they can be solved only by some measure of Government
control of the use of potentially toxic pesticides.
The following three measures are suggested which,
taken together, would seem to offer a possible solution:-
(i) Restriction of Choice of Pesticide. A policy of
reducing the number of potentially toxic residues by
limiting the choice of remedies for any particular
crop to, say, two or three products which have been
recommended by an independent authority.
(ii) Addition of Tracers. A policy of requiring by
Government order the incorporation of an easily
detectable substance with any toxic pesticide before
sale to a user. The use of such "tracers" would
greatly assist analysis.
(iii) Advisory Service. Where no legal standards
have been laid down, local authorities should be
kept advised by the Central Government on which
pesticides are permitted (if the number is to be
restricted); which "tracers" are to be specified
for each permitted pesticide; and the maximum safe
limits, based solely upon public health considerations,
for all permitted pesticides in food.
A weakness of any system for controlling the use of
pesticides in this country would lie in its inability to
cover imported produce but, if the system suggested above
could be successfully applied in this country, the public
would be able to rely upon home-grown produce. Moreover,
such a satisfactorily operating system would doubtless