Dissertation
Tomato is the most consumed horticultural crop in the world due to its economic and
nutritional benefits. The crop is very susceptible to pest infestation making the use of
pesticides during production inevitable. Consumption of tomatoes contaminated with
pesticide residues has been associated with both chronic and acute health risks to human.
This study was aimed at assessing awareness and pesticide residues in tomatoes from
selected markets in Iringa region of Tanzania together with assessing effects of peeling on
reduction of pesticides. Seven pesticides (Profenofose, Chlorpyrifose, Cypermethrine,
Hexaconazole, Lambda cyhalothrin, Endosulfan and Chlorothalonil) were analyzed in
tomatoes by a using Gas Chromatography tandem mass-mass with time of fight (GC-
MSMS-TOF) after extraction with quick, easy, cheap, effective, rugged and safe
(QuEChERS) methodologies. The results showed that all sellers were aware on pesticides
contamination in tomatoes and none of them applied pesticides prior to sell. Peeling
tomatoes reduced pesticide contamination by 35—100% depending on the type of
pesticides and the original pesticide levels before peeling. Thirty-four percent (34%) of
samples didn’t comply with EU MRLs on ʎ- Cyhalothrin, (28%) chloripyrifos, (25%)
hexaconazole and (22%) chlorothalonil. All the samples had lower health risk index,
however cumulatively continuing using tomatoes with low level of pesticides will lead to
increased concentration in the system. Therefore, the proper use of pesticides is
encouraged to minimize residues in the agricultural products that will reduce health risks
upon their consumption.
Director General of Tanzania
Medicine and Medical Devices Authority (TMDA)