Ozone Against Mycotoxins and Pesticide Residues: Food Safety Applications

Background: mycotoxins and pesticide residues in the food supply

Mycotoxins are toxic compounds produced by moulds that colonise crops in the field and during storage; common examples include aflatoxins, deoxynivalenol, zearalenone, fumonisins, ochratoxin A and patulin. Pesticide residues, meanwhile, can remain on fruit, vegetables and grains after agricultural spraying. Both can persist through the supply chain despite good agricultural practice and regulatory limits, and ordinary washing or processing does not always remove them. This has prompted interest in decontamination methods that are effective yet leave no chemical residue of their own. Ozone (O3), a strong oxidising gas that reverts to ordinary oxygen after it reacts, has been studied for exactly this purpose and was recognised as generally safe for food contact in the United States in 2001.

What this review covers

This is a review article rather than a single new experiment. The authors survey published laboratory, pilot and commercial studies on the use of ozone - applied either as a gas or dissolved in water - to reduce mycotoxins and pesticide residues in foods. They draw together evidence across grains, nuts, dried fruit, fresh produce and processed products, describe the underlying chemistry, and summarise reported reductions, effects on food quality and the questions that remain open. Because it synthesises many primary sources, its conclusions reflect the weight of the existing literature rather than one controlled trial.

Findings: how ozone acts on food contaminants

Across the studies reviewed, ozone degraded a broad range of mycotoxins, with reported reductions for aflatoxins, deoxynivalenol, zearalenone, fumonisins, ochratoxin A and patulin in commodities such as cereals, maize, nuts and fruit products. The proposed mechanism is oxidative: ozone attacks the double bonds within these molecules and fragments them into smaller, generally less toxic compounds. The authors note that several cited studies found ozone-treated contaminated feed did not cause toxicity in animal models. For pesticides, the review describes degradation of organophosphates, carbamates, pyrethroids and certain fungicides, with removal rates that varied widely with treatment conditions and, in some water-treatment studies, approached complete removal. Effectiveness depended consistently on ozone concentration, exposure time, temperature, moisture and the food matrix itself. The review is equally clear about trade-offs: ozone can also degrade phenolic compounds and ascorbic acid (vitamin C) and cause colour changes, particularly in fresh produce, so treatment conditions must be balanced against these quality effects.

What the authors concluded

The authors conclude that gaseous ozone and ozonated water are promising, residue-free methods for reducing both mycotoxins and pesticide residues in food, and that ozone's breakdown to oxygen makes it an attractive alternative to some chemical treatments. They stress that conditions must be optimised for each food type in order to maximise contaminant reduction while limiting loss of nutritional and sensory quality. They also call for further research on the degradation pathways involved, the toxicology of the by-products formed, and the economic feasibility of applying ozone at scale before it is adopted more widely across the food industry.

Limitations of this review

As a narrative review, the paper aggregates results from studies that used different ozone doses, exposure times, equipment and foods, which makes direct comparison difficult and prevents any pooled estimate of effect. Much of the underlying evidence comes from laboratory and pilot settings rather than routine commercial production, and reported reductions varied considerably from one study to another. The authors acknowledge that the toxicity of the by-products formed when mycotoxins and pesticides break down is not yet fully characterised, and that ozone's effects on the quality of many foods still need more study. Finally, this work concerns the treatment of food and food-contact surfaces only; it does not examine any health condition or medical use of ozone.