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Completed project

Identify process improvements for preserving peak freshness of broccoli (VG13086)

Key research provider: Applied Horticultural Research
Publication date: Wednesday, December 3, 2014

What was it all about?

Previous consumer research, conducted in VG12045, found purchases of broccoli were significantly reduced by inconsistent quality and freshness at retail. This subsequent study investigated if there was any basis to this perceived issue, and if so, why such inconsistency might be occurring.

Randomly selected retail stores in Sydney, Melbourne, Brisbane and Perth were audited anonymously to assess the type and quality of broccoli displays as well as the quality and temperature of product being sold.

Independent grocers were more likely to display broccoli without refrigeration. The range of display quality was large, ranging from beautifully arranged, multilayered and hand-misted displays to yellowing, physically damaged or excessively large broccoli heads placed directly on a shelf, or even left in the box along with the meltwater they were supplied in. Displays at supermarkets and mini-marts were more uniform, with most using refrigerated or iced displays. Many of the best displays were not refrigerated, but were constructed with evident care for the product.

Broccoli temperatures averaged 10-15oC when displayed in an open environment and around 5oC in a refrigerated unit. However, these averages concealed a huge range of variation and overlap between the methods. Cold temperatures were no guarantee of quality, with some of the highest quality broccoli purchased from open displays and some of the worst from refrigerated units. Around 20 per cent of broccoli at retail was graded as two or less, indicating it was marginally acceptable or poorer quality.

Purchased samples from 56 Sydney retailers including supermarkets, minimarts and independent grocers were trialled in storage at 5oC or 22oC to measure storage and shelf life. Average life was two days at 22oC and fifteen days at 5oC. However, there was huge variability between and even within samples. While some broccoli remained acceptable for up to 30 days, around one quarter would not meet consumer expectations of a minimum seven days storage life at 5oC. Little relationship was evident between display conditions, temperature at purchase or initial quality and subsequent storage or shelf life of broccoli.

Supply chain studies indicated that broccoli is cooled reasonably quickly after harvest, packed cold and transported under well refrigerated conditions. Top icing is still widely used with broccoli packed in styrofoam cartons. This has some advantages but also many disadvantages, particularly industry environmental footprint, potential product damage and cost. Broccoli packed in styrofoam without ice stays warm after packing. Top icing in plasticised cardboard cartons can only be effective if the cold chain is well maintained.

Broccoli has more recently been supplied to some retailers without ice, packed in lined plastic crates. While many in the industry remain reluctant to move to ice-free packing, this appears to be working well with no apparent ill effects on retail quality.

The research concluded that broccoli freshness at retail stores is highly variable. Quality does not relate to display method or price, and storage life cannot be easily predicted from quality at purchase. The source of variability was not clear from the current study, but appears unlikely to be due to poor temperature management in the early part of the supply chain.

Recommendations included developing information for retailers to improve temperature management, handling and display of broccoli, and evaluating different cooling practices on farm.

Related levy funds


Funding statement:
This project has been funded by Hort Innovation

Copyright © Horticulture Innovation Australia Limited 2014. The Final Research Report (in part or as whole) cannot be reproduced, published, communicated or adapted without the prior written consent of Hort Innovation (except as may be permitted under the Copyright Act 1968 (Cth)).