What was it all about?

Leafy vegetables (LVs) are a vital part of a healthy diet, especially when consumed raw. However, their lack of a cooking step makes them particularly susceptible to foodborne contamination. Despite robust post-harvest hygiene practices, outbreaks and product recalls linked to LVs continue to occur, highlighting the need for additional food safety measures earlier in the supply chain. 

This project reviewed current research and industry practices to assess the potential of pre-harvest sanitisation - specifically, the use of chemical sanitisers applied through treated irrigation water or crop sprays- to reduce microbial contamination in the field. 

While some sanitisers showed promise in reducing pathogens, the review revealed significant gaps in evidence around their consistent effectiveness, particularly under real-world conditions. It also raised concerns about possible negative impacts on plant and soil health, the natural microbiome, and overall ecosystem balance. Regulatory, logistical, and practical limitations - such as the difficulty in reaching all leaf surfaces and the risk of re-contamination - were also identified. 

The review concluded that while broad adoption of pre-harvest sanitisation may not be viable under normal conditions, it could have value in high-risk scenarios, such as following extreme weather events. Ensuring the microbial safety of irrigation water through disinfection offers a more practical and immediately actionable strategy for growers. 

To guide future adoption, the development of a tailored risk framework- based on crop type, soil characteristics, and environmental conditions - is recommended. This would help support science-based decision-making and strengthen pre-harvest food safety strategies in leafy vegetable production.  

Watch the project video: Pre-harvest sanitisation of leafy green vegetables (VG22008)