臭氧可用于储存蔬菜水果

Storing fruits and vegetables in ozone¹-enriched environments reduces spoilage²（损坏，糟蹋） explains a scientist at the Society for General Microbiology's Spring Conference in Harrogate. Dr Ian Singleton explains how ozone treatment could be a safe, effective replacement³ for pesticides⁵ as it leaves no residue⁶ on foods. It is estimated that up to 30% of fresh produce can be lost due to microbial spoilage. Dr Singleton from Newcastle University explains that low levels of gaseous⁷ ozone are able to prevent fungal spoilage in a wide range of stored fresh produce, including strawberries, tomatoes, grapes and plums. His work has shown that enriching the storage environment with ozone causes a substantial decline in fungal spore⁸ production as well as a reduction in visible lesions on fruits that are already infected. Fruit stored at low levels of ozone for up to 8 days prevented almost 95% of disease from developing, depending on the fruit and levels of fungal infection.

Fungal contamination（污染） is the most common cause of spoilage of stored fruit, salads and vegetables and the risk of microbial contamination increases with longer storage periods. From the 1950s onwards, heat treatment was replaced with cheap and effective synthetic⁹ fungicides, often used in combination with pre-pack sanitation¹⁰（环境卫生） treatment containing chlorine（氯） or bromine（溴） .

Dr Singleton explains why alternative methods to reduce fungal spoilage are needed. "There are public concerns over pesticide⁴ residues¹¹ on fresh produce. Ozone is a viable¹² alternative to pesticides as it is safe to use and effective against a wide spectrum¹³ of micro-organisms. Importantly, it leaves no detectable¹⁴ residues in contrast to traditional methods of preserving fresh produce."

Interestingly, Dr Singleton's team found that exposing tomatoes to ozone before infecting them with fungus¹⁵ also reduced spoilage. "This suggests that ozone treatment exerts a 'memory' or 'vaccination¹⁶' effect that protects fruit from damage. It is unclear how this phenomenon works, but is certainly worthy¹⁷ of further, detailed¹⁸ investigation," suggested Dr Singleton.

Careful work is also needed to optimize¹⁹ levels of ozone and length of exposure for each variety of produce. "Different fruits have been shown to have different tolerances²⁰ for ozone. We need to look carefully at how we control the atmospheric concentration of the gas in stores and transit containers, since levels of ozone that are too high can damage produce, causing financial losses"