Stability of the dithiocarbamate pesticide maneb in tomato homogenates during cold storage and thermal processing.
The effect of storage at 5 degrees C and of thermal processing by cooking at 100 degrees C and sterilization at 121 degrees C for 15 min on maneb residues in tomato homogenates was investigated. Remaining maneb and its toxic metabolite ethylenethiourea (ETU) were measured after each treatment by headspace gas chromatography with flame-photometric detection and by high-performance liquid chromatography with photo-diode array detection, respectively. No significant loss of maneb was observed during cold storage for up to 6 weeks, taking into account analytical variability. Conversely, thermal treatment resulted in substantial degradation of maneb with extensive conversion to ETU. After cooking, only 26 +/- 1% (+/- SE, n = 8) of initial maneb residues remained in the samples, whilst the conversion to ETU was 28 +/- 1% (mol mol(-1)) (+/- SE, n = 4). Sterilization eliminated the residues of the parent compound giving rise to conversion to ETU up to 32 +/- 1% (mol mol(-1)) (+/- SE, n = 4).
Kontou
S
S
Laboratory of Food Chemistry and Technology, School of Chemical Engineering, National Technical University of Athens, 5 Iroon Polytechniou Str., Polytechnioupoli Zografou, GR-15780 Athens, Greece.
Tsipi
D
D
Tzia
C
C
D003080:Cold Temperature; D004355:Drug Stability; D005504:Food Analysis / Q000379:methods; D005506:Food Contamination / Q000032:analysis*; D005511:Food Handling / Q000379:methods; D005519:Food Preservation / Q000379:methods; D005659:Fungicides, Industrial / Q000032:analysis*; D006358:Hot Temperature; D018551:Solanum lycopersicum / Q000737:chemistry*; D008344:Maneb / Q000032:analysis*; D010573:Pesticide Residues / Q000032:analysis*; D013242:Sterilization; D013696:Temperature
D005659:Fungicides, Industrial; D010573:Pesticide Residues; D008344:Maneb