The efficiencies of washing, preparing and cooking as well as time after
pesticide spraying in the elimination of some pesticides residues from the treated
vegetable were studied. The results indicated some variations in the different used
pesticides and treated vegetables. Higher deposits were detected for the use of
malathion, pirimiphos-methyl and formothion in vine leaves indicating the relation
between the treated surfaces and residues deposits. 'The highest levels of residues were found in vine leaves, while the lowest
values were noticed in tomato fruits. The reduction percentages of the used pesticides
in tomatoes and vine leaves attained the highest values during the first twenty four
hours and tended to decline afterwards. In spite of the high deposits in vine leaves
after one hour post spraying, residues of pirimiphos-methyl showed the highest
reduction rates, followed by formothion+dimethoate and lately came malathion within
the first 24 hours -. The reduction percentage of chlorpyrifos-methyl was also slightly
higher than profenofos that of in tomatoes after one day of application. The residues
of pesticides continued to decrease with the passage time after treatment as the used
pesticide residues in all materials (vine leaves, tomato fruits and potatoes) were
greatly reduced by the prolongation of time. Carbaryl residues of potatoes in tuber pit . . persisted relatively long time. The slow rate carbaryl degradation was related to the
normal condition of tuber pit and not to its stability. The residue half life values were
23 and 21 hours for chlorpyrifos-methyl and profenofos in tomato fruits, respectively.
While these values were 17, 13 and 16 hours for malathion, pirimiphos-methyl and
formothion+ dimethoate -:i1 vine leaves in respective order. This value was 140 for
carbaryl in potatoes in tuber pit condition. Tomatoes could be marketed after 3 days
when treated with chlorpyrifos-methyl and 10 days in case of profenofos spraying.
Vine leaves could be marketed after 6 days post malathion or pirimiphos-methyl but
10 days following formothion application. Carbaryl used for dusting should not be
recommended for human consumption but only for protection potatoes for the new
season cultivation. Washing was efficient in partial elimination of the pesticide residues from
tomatoes and vine leaves after one day post application. Thoroughly washing of
potatoes treated with carbaryl removed most of the initial residues deposit after one
hour post treatment. Boiling vine leaves and concentrating tomato juice for making tomato paste
resulted in complete elimination of the used pesticide residues on the third day after
spraying. Cooking either by boiling or frying and/or combined with washing and
peeling totally removed carbaryl residues from the dusted potatoes even at the initial
time.