Improved strawberry postharvest handling in Australia with new technology (CALM) and cultivars (BS05002)

This is a final research report from Hort Innovation’s historical archives. Please note that as these reports may date back as far as the 1990s, the content and recommendations within them may be superseded by more recent research.

What was it all about?

Australia had a world class strawberry breeding program and new higher flavour local and overseas developed cultivars were developed that could be grown in Australia. It had been suggested that the newer, higher flavour cultivars had higher losses during marketing. This had been examined in this work. For the first time in Australia a detailed comparison, was made of some of the major cultivars grown in Australia. Also postharvest quality with regards to rots and flavour of fruit was investigated as it was felt after the excellent breeding that postharvest quality was potentially a bottleneck that could adversely effect sales.

The project also examined the quality of strawberries commonly found in the market in several Australian capital cities. Problems with immature fruit (and consequently poor flavour) and rots were commonly found. The effect of individual grower was found to be more significant than district or cultivars on immaturity and rots. The higher flavoured and sweeter cultivars were not found in this research to be any more susceptible to rots and postharvest losses than cultivars with lower sugar content and flavour. This suggested that with adequate disease control, the newer sweeter strawberry cultivars could be marketed with no increased losses to the strawberry industry. It was found that fully mature and ripe strawberries (i.e. fully red with no white or green patches) had much higher flavour, sugars and aroma levels but that they were slightly more susceptible to rots than immature strawberries that were being marketed by some growers. Therefore some postharvest disease control was very important in marketing high flavour, fully mature strawberries. Rubygem, an Australian bred strawberry, was found to had high levels of the most important strawberry aroma compounds.

This project had developed new and improved postharvest handling methods for the Australian strawberry industry. This had occurred in two ways. Firstly, the CALM storage technology developed recently in Australia for chestnuts had been extensively modified and optimised for strawberries. The maintaining of a high carbon dioxide and low oxygen atmosphere around the strawberries had considerably extended their storage life. Secondly, new handling and disease control measures based on hot water or sanitisers had been developed that compliment the CALM technology. The two technologies combined together had the pontential to greatly extend strawberry storage life and improve the deliverable quality of strawberries to the consumer.