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Avocado Fruit Harvesting, Handling and Storage Practices in Australia

Avocado Fruit Harvesting, Handling and Storage Practices in Australia

Product Type: Fruit - Avocado
Stage:  Handling & Storage

Problem

Avocado industry has faced with a challenge that the fruit is easily get bruised in its mesocarp. The issue has remained the most negative experience of avocado consumers in Australia. In a survey, consumers reveal that up to one in three of purchased avocados is a disappointment. 

 


Factors affecting avocado flesh bruising susceptibility

1.      Scientists have proved that bruise happen when avocados are dropped at certain level in their specific level of firmness. For instance, hard green fruit impacted from up to 100 cm drop high does not express visible bruising symptoms while the greater bruising severity happen on ripening fruit with the same impact.

2.      Harvesting avocado at the recommended stage of maturity of >= 23% dry matter content could reduce the fruit susceptibility to mesocarp bruising.

3.      Factors increasing mesocarp bruising in avocado cv. Hass:

        Lower fruit maturity and fruit firmness,

        Longer pre-ripening fruit holding duration (up to 6 weeks) and post- ripening fruit holding durations (up to 7 days)

        Higher fruit holding temperature (above 5º C

4.      All the bruise happen at the store level, mainly by the squeeze of customers during fruit selection. In a survey of Australian avocado consumers, 97 percent admitted to squeezing the fruit before purchasing it.

 
Solution

1.      Best practices in handling and transportation avocado

Ø   Harvesting

Hass fruit must contain at least 23% dry matter and Shepard fruit must contain 21% dry matter for marketing in most Australian states. However, fruits will be more palatable and have a better flavour if allowed to reach dry matter levels 3% to 5% higher than the 21% level. The standard also requires that fruit must ripen without shrivelling and decay. Check the maturity of the crop before harvesting by doing a ripening test and a dry matter test.

Avocados are picked by hand using ladders, picking poles and, where slopes permit, hydraulic picking platforms or cherry pickers. It is important to make sure pickers have sufficient knowledge of what is required. Some key pieces of knowledge are:

 

  • Avoid picking during wet weather as fruit are more susceptible to skin damage and fungal infection.
  • Avoid picking during extremely hot weather (above 30°C) if fruits are to be cool stored for more than two weeks as fruit are more susceptible to breakdown.
  • Cut the fruit from the tree using avocado snips, secateurs or shears, leaving 3 to 4 mm of stalk intact (for all varieties other than Hass).
  • Pick in several lots if the fruit is not a uniform size. Remove large fruit first, allowing remaining small fruit to increase in size. Harvest at least 50% of fruit within one to two months of it reaching maturity. This is important where trees set heavy crops because trees may be pushed into an alternate-bearing pattern.
  • Keep harvested fruit under shade.

 

Ø   Cooling

In general, cool fruit if the period between harvest and delivery at the intended market is more than two days. This means that all fruit marketed outside the local area generally requires cooling. The general aim is to cool hard, green mature fruit to the following temperatures:

  • 4°C to 5°C for Hass
  • 6°C to 8°C for other varieties.

In general, cool fruit to the required transport temperature within 48 hours of harvest. However, if fruit is to be stored for longer than five days, cool fruit to the required storage temperature within 24 hours of harvest. Always check with your marketers to ensure that on-farm cooling practices are compatible with market handling conditions.

Ø   Storage

Storage is the holding of cooled fruit before transport to customers (wholesalers, retailers, exporters). The optimum temperature range and the maximum storage time for avocados varies with variety:

Variety

Optimum storage temperature

Maximum storage time

Hass

4°C to 5°C

4 weeks

Other varieties

6°C to 8°C

2 weeks

Avocados ripen quickly when they are removed from storage to normal air temperatures. For example, fruit removed from storage after two weeks and warmed to 20°C will ripen in about half the time as fruit held at 20°C immediately after harvest.
Daily monitoring of air and fruit temperatures is necessary to check the storage process. Keep a temperature log to provide evidence on whether storage has been effective. For long storage periods, check the fruit condition for any signs of ripening.

Controlled atmosphere (CA) conditions can extend the storage period for Hass. By reducing the oxygen level to 2% to 5% and maintaining the carbon dioxide level between 4% and 10%, a storage life of up to six weeks can be achieved. Specialized equipment and precise monitoring of the temperature and atmosphere is required. Only high quality fruit should be placed into CA storage.

2.      Avocado display and merchandising at store:

1) Displays sorted by stages of ripeness.

2) Ripe fruit consistently available.

3) Colored stages of ripeness foam pads.

4) “Eat Now” and “Eat Later” header cards.
Source: Applied Horticultural Research (AHR)

 

Resource :

M. Mazhar, D. Joyce, P. Hofman, and N. Vu (2018). Factors contributing to increased bruise expression in avocado (Persea Americana M.) cv. ‘Hass’ fruit. Postharvest Biology and Technology 143, 58-67. https://doi.org/10.1016/j.postharvbio.2018.04.015

Department of Agriculture and Fisheries, Queensland Government: https://www.daf.qld.gov.au/business-priorities/plants/fruit-and-vegetables/fruit-and-nuts/avocados/cooling-and-storage

Applied Horticultural Research: http://ahr.com.au/

Avocado picker’s guide: https://www.youtube.com/watch?v=v-wmGGuy_Iw

Avocado display and merchandising guideline: http://ahr.com.au/wp-content/uploads/2018/06/Appendix-14-Avocado-Display-and-Merchandising-Chart.pdf

New Avocado Merchandising Concepts: http://ahr.com.au/wp-content/uploads/2018/06/Appendix-9-Avocado-Merchandising-Set-Up-instructions.pdf

Bruising in Australian Avocados: https://www.youtube.com/watch?v=yDn-4YbV9BE