FAO/PL:1969/M/17/1
WHO/FOOD ADD./70.38
1969 EVALUATIONS OF SOME PESTICIDE RESIDUES IN FOOD
THE MONOGRAPHS
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
Group on Pesticide Residues, which met in Rome, 8 - 15 December 1969.
FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS
WORLD HEALTH ORGANIZATION
Rome, 1970
PYRETHRINS AND PIPERONYL BUTOXIDE
Explanation
These pesticides were evaluated by the 1966, 1967 and 1968 Joint
Meetings (FAO/WHO, 1967b, 1968b, 1969b).* At the Fourth Session (1969)
of the Codex Committee on Pesticide Residues the delegation of Canada
pointed out the need for tolerances for residues of pyrethrins and
piperonyl butoxide on dried codfish. Supporting data were submitted
and evaluated at this 1969 Joint Meeting.
RESIDUES IN FOOD AND THEIR EVALUATION
CODFISH
The use of pyrethrins piperonyl botoxide emulsions to protect light
salted codfish from blow fly attack during the drying process is
practised in Newfoundland and possibly elsewhere. The technology for
protection against the species Lucillia illustris (Meig) and
Calliphora terranovae (Macq.) has been described (Morris and
Andrews, 1968). Fish taken from brine barrels are washed in salt water
and dipped in insecticide emulsion for 3-5 seconds. They are
immediately spread on trays to dry in the sun and wind. Recently it
has been found possible to reduce the concentration of insecticide in
the emulsion to 0.0625 percent pyrethrins and 0.125 percent piperonyl
butoxide (technical) and still maintain protection.
Residues resulting from supervised trials on codfish
Fifty fish were dipped in the emulsion (0.0625 percent pyrethrins,
0.125 percent piperonyl butoxide) and fifty fish were left untreated
as checks on 14 September 1968. Following drying in regular commercial
manner, treated and untreated fish were sampled on 23 October and
shipped by air for analysis. The analyses were carried out by a method
reported by McGlaughlin Gormley King Co. based on the use of a gas
chromatographic method and detector cell described by Bruce (Bruce,
1967). Replicated analyses showed levels of 0.051 to 0.066 ppm
pyrethrins and 0.76 to 0.97 ppm piperonyl butoxide (0.87 to 1.1 ppm
technical) in the fish. This is representative of residues in the
product as moving in commerce. Such fish would be soaked or boiled in
water before consumption.
Methods of residue analysis
The methods of analysis outlined above should be evaluated for use as
regulatory methods. They have been reported to the IUPAC Commission on
Development, Improvement and Standardization of Methods of Pesticide
Residue Analysis.
FRESH FRUIT AND VEGETABLES
The new data that had been mentioned at the Fourth Session of the
Codex Committee on Pesticide Residues were not available for
consideration at the meeting. Whilst examining the data available it
was noted that the monograph for the 1968 meeting (FAO/WHO, 1969b)
contained the reservation "for canning only" against the
recommendation for a tolerance for piperonyl butoxide but not for
pyrethrins.
Recommendation
After discussion it was decided that the limiting words should be
deleted from the recommendations pertaining to piperonyl butoxide.
RECOMMENDATIONS FOR TEMPORARY TOLERANCES
The following temporary tolerances, to be in effect until 1972:
a) Dried codfish moving in commerce:
pyrethrins - 0.1 ppm
piperonyl butoxide - 1.0 ppm
b) Fresh fruit and vegetables (amendment)
The words "for canning only" should be deleted from the
recommendations included in the records of previous meetings,
FURTHER WORK REQUIRED (by 30 June 1972)
In addition to "Further Work" included in FAO/WHO 1967b) and 1968b,
experience and residue data from similar trials with dried fish in
other countries.
REFERENCES
Bruce, W.N. (1967) Detection cell for measuring picogram quantities
of organophosphorus insecticides, pyrethrins synergists and other
compounds by gas chromatography. J.Agr.Fd.Chem. 15: 178-81
Morris, R.F. and Andrews, D. (1968) Investigations into the use of
pyrethrins and other insecticides for the control of blowfly.
Calliphura terranovae (Macq.) infesting light salted codfish in
Newfoundland. Purethrum Post 9: 9-13
* See Appendix II