Residues of Nine Insecticides and Two Fungicides in Raw and Processed Tomatoes

Area of Science:

• Agricultural Chemistry
• Environmental Science
• Food Safety

Background:

• Pesticide use in agriculture necessitates understanding residue levels in food products.
• Regulatory limits for pesticide residues in raw produce and processed goods must be met.
• Establishing preharvest intervals (PHI) is vital for ensuring consumer safety and compliance.

Purpose of the Study:

• To determine preharvest intervals for nine insecticides and two fungicides in raw tomato fruit and juice.
• To ensure residue levels remain below 0.1 mg kg^-1 for raw fruit and 0.01 mg kg^-1 for juice.
• To evaluate the efficacy of various PHIs in reducing pesticide residues.

Main Methods:

• Commercial tomato crops were treated with 11 different pesticides (9 insecticides, 2 fungicides).
• Tomatoes were harvested at various intervals (0, 1, 3, 6, 7, 8 days post-application).
• Residue analysis was performed on both raw tomato fruit and processed juice.

Main Results:

• Most pesticides declined below 0.1 mg kg^-1 in juice and raw fruit within 8 days.
• Exceptions for raw fruit included chlorothalonil, diazinon, and azinphosmethyl in 1987.
• Seven insecticides and two fungicides fell below 0.01 mg kg^-1 in juice, but only acephate and demeton met this for raw fruit within 6-8 days.
• Carbaryl and malathion did not decline below 0.01 mg kg^-1 in juice.
• Commercially processed tomato products showed no detectable residues.

Conclusions:

• Many tested pesticides require preharvest intervals longer than 6-8 days to achieve residue levels below 0.01 mg kg^-1.
• Specific insecticides and fungicides necessitate longer waiting periods to meet safety standards.
• Further research into extended PHIs is needed for certain pesticide-commodity combinations.