Between Rumor and Fact - What Do We Know About Pesticide Residues in Oils?

Kamal was speaking with great enthusiasm, making sweeping generalizations without scrutiny:

Kamal:"Look, stay away from olive oil! It's all pesticides and chemicals from the moment it's grown, and when it's pressed, the contaminants remain. If you absolutely must, only use the second pressing. And corn oil? Same story. They're all contaminated oils, unfit for human consumption. The only solution is to grow, press, and package it yourself."

Engineer Essam, a food science expert, smiled, then replied calmly:

Engineer Essam:"Kamal… your statements heavily confuse scientific facts with rumors. Let's get to the bottom of this, because oils – whether olive oil, corn oil, or others – are subject to very strict standards, and what you're saying about pesticides is not scientifically accurate. Let's take it step by step."

Do pesticides remain in oils? And what are the permissible levels?

Do pesticides transfer from fruits to oil?Pesticides used in agriculture vary in their chemical composition, and therefore, their ability to transfer to oil differs. The crucial factor here is "pesticide solubility":

• Water-soluble pesticides: They mostly remain in the fruit's aqueous sap and do not transfer to the oil.
• Fat-soluble pesticides: They may transfer to oil in limited proportions, but they are subject to strict regulation.

The rate of pesticide transfer to oil is usually very low due to:

• Washing processes before pressing.
• Partial degradation of pesticides.
• The already low doses used.
• Regulations that prohibit the use of highly fat-soluble pesticides on oil crops.

Degradation Periods (PHI) – The Key to Safety

Every pesticide has what is called: Pre-Harvest Interval (PHI)This is the period that must elapse between the final pesticide application and harvest.

During this period:

• The pesticide gradually degrades.
• Its concentration drops to safe levels.
• Farmers are prohibited from harvesting before this period has ended.

Some pesticides degrade within 3–7 days, while others require 14–21 days. Long-lasting pesticides may need a month or more, but these are generally prohibited for oil crops.

Are pesticides detectable in the final oil?

Yes, very minute traces of some pesticides may appear, but they remain within globally permissible limits set by regulatory bodies such as:

• Codex Alimentarius.
• Saudi Food and Drug Authority.
• U.S. Food and Drug Administration.
• The European Union.

Maximum Residue Limits (MRLs) for pesticides typically range between:

• 0.01 – 0.5 mg/kg.
• And in rare cases, may reach 1 mg/kg.

Any product exceeding these limits is immediately withdrawn from the market.

Heavy Metals… Another Source of Concern

Heavy metals like lead, cadmium, and mercury usually do not originate from pesticides, but rather from:

• Contaminated soil.
• Irrigation water.
• Old equipment.

These elements are also subject to strict limits, and their proportions in commercial oils are often much lower than the permitted limit, as shown in the following table:
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Olive Oil… Between Fact and Claim

Despite rumors, olive oil – especially extra virgin – is one of the most globally regulated oils. It is cold-pressed without chemical additives, and pesticide residues are regularly checked.

As for the idea that "the second pressing is cleaner," this is incorrect information; The first pressing is of the highest quality and nutritional value.

Conclusion

• Pesticides decompose within specific periods before harvest.
• What may reach the oil is within globally safe limits.
• Olive oil is one of the safest and highest quality oils.
• Science relies not on impressions, but on analysis, regulation, and testing.

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