1968 EVALUATIONS OF SOME PESTICIDE RESIDUES IN FOOD
Issued jointly by FAO and WHO
The content of this document is the result of the deliberations of the
Joint Meeting of the FAO Working Party of Experts and the WHO Expert
Committee on Pesticide Residues, which met in Geneva, 9-16 December,
FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS
WORLD HEALTH ORGANIZATION
Since the previous evaluation (FAO/WHO, 1968) additional data have
become available and are summarized and discussed in the following
RESIDUES IN FOOD AND THEIR EVALUATION
The 1967 Joint Meeting recommended a temporary tolerance of 0.5 ppm
diazinon in meat (fat basis). At the Third Session of the Codex
Committee on Pesticide Residues, the delegation of Australia proposed
that the temporary tolerance should be increased to 0.75 ppm in meat
(fat basis) (CCPR, 1968). It was agreed that Australia should submit
to the FAO Secretariat data justifying an increase in the recommended
tolerance (Australia, 1968).
Diazinon is applied in the form of emulsions and wettable powders for
the control of ticks, lice, flies, mosquitos and sand-flies attacking
cattle. The preparations are applied as sprays or in the form of dips
through which the animals must swim. The concentration used for such
treatment ranges from 0.04 per cent to 0.1 per cent.
Residues resulting from supervised trials
Robbins et al. (1957) showed, by using 32P- labelled diazinon, that
the insecticide is metabolized and excreted when fed to a cow. Studies
by Rai and Roan (1962) using conventional chemical methods as well as
32P- labelled diazinon showed that no significant residues occurred
in animal tissues when diazinon was administered in feed. Harrison and
Hastie (1965) showed that there were no significant residues in the
milk of cows and fat of sheep feeding on pasture treated by diazinon.
Hastie (1963a and b) reviewed recent work on diazinon residues in the
meat and fat of sheep and cattle and in the milk of cows following
dipping or spraying. The extensive trials reported show that the
residues of diazinon in subcutaneous fatty tissue of sheep and cattle,
treated for parasite control, do not exceed 0.75 ppm even one day
after treatment. However, internal fat from such animals may contain
over 1 ppm following dipping or spraying. The average residue level
declines rapidly following treatment but samples from individual
animals may exceed 0.75 ppm for more than 14 days. Hastie (1965)
showed that standard treatment procedures resulted in residues
in excess of 1 ppm in the fat of sheep one day post-treatment.
After three days it has declined to 0.3-0.5 ppm.
Claborn et al. (1963) showed that cattle sprayed with diazinon had
residues of 0.75 ppm in omental fat six days after treatment but that
the level declined rapidly thereafter. After 14 days the level had
fallen to less than 0.1 ppm.
Diazinon has been used for a number of years as a treatment of sheep
and cattle against external parasites in Australia, New Zealand, South
Africa, Argentina, Brazil and Uruguay. To a lesser degree it has been
used in the United States of America, Canada, Mexico, and the United
Kingdom and other countries for similar purposes.
Country Product Tolerance (ppm)
Australia Meat (fat basis) 0.75
of America Meat (fat basis) 0.75
RECOMMENDATIONS FOR TOLERANCES AND PRACTICAL RESIDUE LIMITS
The meeting considered new data on residues found in cattle that had
been treated against ectoparasites in Australia and other countries.
Results from applications by spraying and dipping animals were
considered. The residues from plunge treatment tend to be greater than
those from spraying but the meeting took the view that it would not be
practical to consider only the latter figures.
According to Hastie (1965) the maximum residues in omental and kidney
fat after plunge treatment were 0.9 and 0.38 ppm by the third and
eighth day respectively.
Figures for diazinon in objective commercial samples of fat of sheep
in Australia were also considered. They showed only a very small
proportion to exceed 0.75 ppm.
The meeting confirms the previously recommended temporary tolerances
(FAO/WHO, 1968) to be in effect until 1970 and in the case of the
tolerance in meat (on a fat basis) recommends that the figure be
raised from 0.5 to 0.75 ppm.
The above temporary tolerances are to apply to raw agricultural
products moving in commerce unless otherwise indicated. In the case of
fruit and vegetables the tolerances should be applied as soon as
practicable after harvest and in any event prior to actual retail to
the public. In the case of commodities entering international trade,
the tolerances should be applied by the importing country at the point
of entry or as soon as practicable thereafter.
Australia. (1968) Submission to 1968 Joint Meeting of the FAO Working
Party of Experts and the WHO Expert Committee on Pesticide Residues.
Prepared by the Australian Delegation to the Codex Committee on
CCPR. (1968) Report of the Third Session of the Codex Committee on
Pesticide Residues; (ALINORM 69/24)
Claborn, H. V. et al. (1963) Diazinon residues in the fat of sprayed
cattle. J. Econ. Entomol., 56: 858-859
FAO/WHO. (1968) 1967 evaluations of some pesticide residues in food
(FAO, PL:1967/M/11/1; WHO/Food Add./68.30)
Harrison, D. L. and Hastie, B. A. (1965) Diazinon residues in milk of
cows, and fat of sheep after feeding on pasture treated with diazinon.
New Zealand, J. Agr. Res., 9: 1-7
Hastie, B. A. (1963a) Diazinon residues in sheep and cattle.
Publication by Geigy Agricultural Chemicals, Botany, Australia
Hastie, B. A. (1963b) Diazinon residues in fat of cattle following
dipping. Geigy report 63/7/162
Hastie, B. A. (1965) Diazinon residues in sheep fat. Geigy report
Rai, L. and Roan, C. C. (1962) Report to NC-33 Regional Technical
Committee from Department of Entomology, Kansas State University,
Kansas, United States of America
Robbins, W. F., Hopkins, T. L. and Eddy, G. W. (1957) Metabolism and
excretion of 32P labelled diazinon in a cow. J. Agric. Food Chem.,