Ozone Treatments for Preserving Fresh Vegetables Quality

Background: why fresh vegetables spoil after harvest

Fresh vegetables continue to respire and deteriorate once they are picked, and a large share of the global harvest is lost between field and plate. Spoilage and pathogenic microorganisms shorten shelf life and raise food-safety concerns, so growers, packers and retailers rely on washing, sanitising and cold storage to slow that decline. Conventional chemical sanitisers such as chlorine are effective but can leave residues and by-products, which has driven interest in alternatives that control microbes without leaving a chemical trace. Ozone - a highly reactive form of oxygen that breaks back down into ordinary oxygen - is one such alternative, and it is the subject this review sets out to assess.

Study design: a critical review of ozone applications on vegetables

Elodie Sarron, Pascale Gadonna-Widehem and Thierry Aussenac, based at Institut Polytechnique UniLaSalle in Beauvais, France, carried out a critical review of the published literature on ozone treatment of fresh vegetables. Rather than reporting a single experiment, the paper gathers and weighs studies covering both gaseous ozone and ozone dissolved in water (ozonated water), the ways ozone acts on microbial cells, and the process conditions - concentration, exposure time, temperature and humidity - that determine whether a treatment works. It was published in the journal Foods in March 2021.

Findings: antimicrobial action that depends heavily on conditions

The authors describe ozone as a broad-spectrum antimicrobial whose power comes from its oxidative capacity: it attacks proteins, lipids, enzymes, nucleic acids, cell membranes and other cellular constituents, which allows it to control the spoilage and pathogenic microorganisms that limit vegetable shelf life. In both gaseous and water-solubilised forms, ozone can reduce microbial loads while helping to preserve quality characteristics. The recurring theme, however, is variability: the performance achieved in practice is very strongly dependent on how the treatment is implemented. Ozone dose, contact time, temperature, humidity and the nature of the produce itself all shape the outcome, and conditions that are too aggressive can oxidise and damage the vegetables rather than simply protect them.

What the authors concluded

The review concludes that ozone, in gaseous or dissolved form, can be a useful tool for preserving fresh vegetables - both by controlling microbial growth and by helping to maintain quality - because of its oxidative, antimicrobial action and the fact that it decomposes back to oxygen without leaving a chemical residue. The authors stress that this potential is only realised when the general conditions of application are properly controlled and optimised for the specific product, since effectiveness and safety both hinge on getting the dose and exposure right.

Limitations of this study

As a critical review, the paper synthesises and interprets existing studies rather than generating new experimental data, so its conclusions are only as robust as the literature it draws on. Results across the field vary with produce type, ozone source and measurement methods, which makes direct comparison difficult and means findings cannot always be generalised from one vegetable or set-up to another. The review also highlights that ozone's oxidising nature is double-edged: the same reactivity that kills microbes can degrade colour, texture and nutritional quality if doses are excessive, so optimal conditions must be established case by case. The paper addresses food preservation and surface decontamination of vegetables only, and does not concern human health or any medical use of ozone.