Low temperature shipping and cold chain management of 'Fuerte' avocados: An opportunity to reduce shipping costs

Shipping at low temperatures (2oC) can reduce the risk of poor internal quality often associated with greenskins. However, at these low temperatures external chilling injury occurs, a serious problem for the export of cultivars such as ‘Fuerte’. Previously an interaction between post-harvest water loss and skin damage has been reported. Furthermore, the effect of commonly occurring cold chain breaks (and subsequent water loss) on fruit quality at these low temperatures was investigated. ‘Fuerte’ avocado fruit were stored at low temperatures (2oC and 5.5oC), treated with 1-MCP and / or waxed. Additionally, commonly occurring cold chain breaks (24 hour cooling delay, break for 8 hours at 5, 10 or 20 days) were simulated. Fruit were analysed with respect to fruit softening, mass loss, CO 2 evolution, days-to-ripening, as well as external and internal quality. The storage temperature of 2oC provided good internal quality, reduced mass loss and fruit softening, as well as an extended shelf life, compared with the 5.5oC fruit. The 2oC storage temperature caused a notably higher occurrence of external chilling injury than 5.5oC, however, waxing reduced the amount of external chilling injury signifi cantly. Cold chain breaks caused fruit softening and water loss with the most harmful break being a 24 hour delay in cooling, which resulted in a high water loss and fruit softening and, thus, the highest external chilling injury. Overall, ultra-low temperature storage shows promise, and if the external chilling injury can be successfully reduced at 2oC by use of mitigating treatments, the South African avocado industry could realise substantial savings.