Degradation of parathion methyl on field-sprayed apples and stored apples.
Residue levels of parathion methyl on field-sprayed Granny-Smith apples were studied. The pesticide was applied according to producer recommendations. Apples received a single spraying at a rate of 40 g active ingredient/100 L. Residues were determined with a simple gas chromatographic method. Recovery of parathion methyl was 88-108%, and the limit of determination was 0.002 mg/kg. Decomposition of parathion methyl was studied in apples remaining on trees after spraying and in apples harvested and stored under ambient-temperature, refrigerated-room, and controlled-atmosphere conditions. During post harvest storage, parathion methyl degrades more slowly than on apples remaining on the trees. Best-fit curves were determined, and kinetic equations, rate constants, and half-lives were calculated. Half-lives found were 8 days for apples on trees, 45 days for apples stored at ambient conditions, 68 days for apples stored in controlled-atmosphere room, and 62 days for apples stored in a refrigerated room. Under storage conditions, levels of parathion methyl residues need a long time to become lower than the legal limit (0.2 mg/kg).
Pappas
C J
CJ
Agricultural University of Athens, Department of Food Science and Technology, Greece.
Kyriakidis
N B
NB
Athanasopoulos
P E
PE
D002849:Chromatography, Gas / Q000379:methods; D003080:Cold Temperature; D005519:Food Preservation; D006207:Half-Life; D007306:Insecticides / Q000032:analysis*; D007700:Kinetics; D008743:Methyl Parathion / Q000032:analysis*; D010573:Pesticide Residues / Q000032:analysis*; D019685:Rosales / Q000737:chemistry*; D013696:Temperature; D013997:Time Factors
D007306:Insecticides; D010573:Pesticide Residues; D008743:Methyl Parathion