Supply chain quality improvement – cool chain best practice guidelines (AV15010)

What was it all about? 

This work was one component of a three-part industry supply chain quality improvement program, and was designed to…

• Increase the adoption of best-practice in cool-chain management and post-harvest handling across all sectors of the avocado supply chain, from orchard to retail
  
  
• Help reduce the incidence of rots and other quality defects in avocados
  
  
• Increase the awareness of factors that predispose fruit to quality defects across the supply chain.

In its course, the project produced four new guides and resources for the industry, which are available for download via the industry’s Best Practice Resource (BPR). They include…

• A detailed review of Australian and international research on pre- and postharvest management factors affecting avocado quality
  
  
• The Australian Avocado Supply Chain Best Practice Guide – a concise guide for postharvest best practice from orchard to retail
  
  
• The Avocado Fruit Quality Problem Solver Guide – a postharvest guide focusing on fruit quality issues
  
  
• A series of risk-preventing checklists for each stage of the supply chain.

Printed copies of these materials were made available at industry workshops, and can also be requested by contacting Applied Horticultural Research’s Sandra Marques at sandra.marques@ahr.com.au.

The resources were informed by delving into international and local research on managing avocado quality, along with industry consultation to understand how avocados are currently managed, and a series of studies involving Australian avocado businesses. The research involved 12 packhouses in five growing regions, examining impacts during harvest, sources of postharvest damage, and temperatures in supply chains from farm to retail. Key findings included…

• Significant impacts can potentially occur when harvesting from mechanical work platforms if the bag is left at full extension – and restricting the bag around the middle and releasing fruit gradually should prevent damage.

• Most impacts on packing lines were below damage thresholds, however, it was found that overloading fruit on the line and excessive brushing increased lenticel damage on Hass fruit.

• Room cooling of bins of avocados is relatively slow, with large differences between the centre and outside of the bin – but these can be eliminated using forced-air cooling.

• Fruit pulp temperature at dispatch was above 6°C in the majority of the supply chains monitored, and above 10°C in some.

• Only one of the supply chains monitored maintained fruit temperature at 5°C during transport, with the majority averaging 8 to 12°C with significant variation occurring. In many cases, fruit temperature rose during transport, suggesting that truck cooling systems were inadequate to cope with heat generated by the avocado fruit.

• Ripening temperatures were variable, with the best results gained when ripening rooms were equipped with forced-air systems for heating as well as cooling fruit.

The results fed into the development of a range of best practices that avocado businesses can implement. As a sample, these include…

• Pre-harvest: Reduce the risk of rots through an effective fungicide program and maintaining healthy trees
  
  
• During harvest: Avoid dropping fruit; avoid picking when fruit are wet; clip rather than snap-pick if disease pressure is high
  
  
• Packhouse: Avoid delays in cooling between harvest and packing; use post-harvest fungicide immediately after harvest; pick and pack within 24 hours; immediately forced-air-cool fruit to 5 to 7°C
  
  
• Transport: Minimise breaks in the cool chain; maintain temperature at 5 to 7°C; use temperature loggers to verify the system is working
  
  
• Wholesaler: Minimise fruit age (days from harvest)
  
  
• Ripener: Ripen between 16 to 20°C, using the lower end of the range for mature fruit at risk of rots; store sprung fruit at 5°C; minimise holding time
  
  
• Retail: Store ripe fruit at 5°C; minimise storage time.