With globalisation of the fresh vegetable trade and consumer demand for clean, safe, and fresh foods, there is strategic opportunity for Australian producers to capitalise on our clean and green image to access higher-value, discriminating markets. Growers generally recognise that a washing step can enhance the market quality of many fresh vegetables and in a national survey of 5000 vegetable growers, we found that sanitisers are now widely used. Sanitisers are used to reduce postharvest rot and reduce the concentrations of bacteria linked to human disease. When used properly, sanitising chemicals are sage for consumers and the environment. However, many growers indicated they wanted more information on the ‘best practice’ use of sanitisers and on alternative sanitisers to chlorine.

In response, we have conducted research to help achieve ‘best practice’ hygienic postharvest systems for vegetable and tomato growers. This research has shown the:

• comparative effectiveness, safety, and registration status of sanitisers
• principles and practices of effective disinfection
• appropriate methods for safe disposal of used sanitisers

Research demonstrated that sanitisers destroy up to 99% of harmful bacteria on fresh produce and totally eliminate bacterial and fungal pathogens from wash water. However, the performance of washing systems depends on the quality of the supply water and the ability to control water quality in recirculated systems. In particular, growers and packers may need to consider controlling the temperature, pH, and organic load in their wash systems.

Another aspect of the project was to identify alternatives to chlorine and fomalin as water and surface disinfectants respectively. Chlorine dioxide, bromochlorine, ozone, peracetic acid, iodine, quaternary ammonia compounds, and non-chemical treatments were evaluated.

In parthership with manufacturers new hydrocooling and washing systems we develop and evaluated. For many vegetable types, rapid establishment of the cold chain greatly reduces the risk of rots and microbiological contamination.

Workshops were held in five states to encourage the adoption of ‘best practice’ for hygienic postharvest and growers have been informed of project developments via a newsletter and booklet.