Effects of ozone treatment on pesticide residues in food: a review

Background: pesticide residues on the food we wash and eat

Pesticides are widely used to protect crops, but residues can remain on fruit and vegetables after harvest. Because these foods are often eaten with minimal processing, researchers have looked for practical ways to reduce residues at home and in the food industry. Ozone, a strong oxidising form of oxygen that leaves no lasting chemical residue of its own, has attracted interest as one such method.

What this review covers

This is a narrative review that draws together published studies on the use of ozone to break down pesticide residues in food. It examines ozone applied both as a gas and dissolved in water, sets out the chemistry by which ozone attacks different classes of pesticide, and considers the factors that influence how well the treatment works, including ozone concentration, treatment time, temperature, pH and the type of food being treated. The authors also weigh the potential downsides, such as breakdown by-products and effects on food quality.

Findings reported across the studies

The review reports that ozone can degrade a range of pesticide residues, with the degree of removal depending strongly on the conditions used and the chemical structure of the pesticide. Higher ozone concentrations and longer contact times generally increased degradation, while the form of ozone (gaseous or aqueous), temperature and pH all affected the outcome. The authors describe the mechanisms involved, in which ozone and the reactive species it generates attack particular chemical bonds within pesticide molecules. They also note that degradation is not always complete and can produce intermediate compounds, and that treatment may affect the sensory and nutritional quality of some foods.

What the authors concluded

Having weighed the advantages against the disadvantages, the authors conclude that ozone treatment is a promising method for degrading pesticide residues in food. They recommend it as a practical approach, while stressing that treatment conditions need to be matched to the food and pesticide involved, and that the nature of any breakdown products deserves further attention.

Limitations of this review

This is a narrative review rather than a systematic review or meta-analysis, so it does not apply a formal protocol to search, weight or pool the underlying studies. The primary studies it summarises used varied foods, pesticides, ozone forms and measurement methods, which makes direct comparison difficult and limits how firmly general conclusions can be drawn. The authors themselves highlight that the identity and safety of degradation by-products, and the effects of ozone on food quality, remain areas needing more research.