Cryogenically Frozen Avocados Offer a Food Security Solution

A scientific breakthrough could promise to secure the supply of smashed avo on toast for future generations.

An Australian PhD student has developed what’s claimed to be the first crucial steps to create cryopreservation protocol for avocado which had never been achieved until now, despite more than 40 years of research.

It's the same cryopreservation technology used to freeze human biological material such as sperm and eggs at minus 196 degrees Celsius by placing them in liquid nitrogen. Cryonics has been used in the past to freeze other produce such as bananas, grapevines, and apple. It now offers a method of safeguarding the supply of the beloved, green superfood.

“The aim is to preserve important avocado cultivars and key genetic traits from possible destruction by threats like bushfires, pests, and disease such as laurel wilt, a fungus which has the capacity to wipe out all the avocado germplasm in Florida,” explained University of Queensland PhD student Chris Obrien.

Liquid nitrogen does not require electricity to maintain its temperature, therefore successfully freezing avocado germplasm is an effective way of preserving clonal plant material for an indefinite period.

O’Brien began by using a clonal shoot tip developed from tissue culture propagation technology, a technique used to maintain plant cells. This enables up to 500 avocado plants to grow from just one shoot-tip.

Eventually, he placed the shoot tips on an aluminium foil strip, which meant they could quickly cool and rewarm without becoming slush.
They were then placed into a cryotube begore being stored in liquid nitrogen. The frozen shoot tips were later revived in a petri dish containing a sucrose mixture to rehydrate.

“It takes about 20 minutes to recover them,” said O’Brien. “In about two months they have new leaves and are ready for rooting before beginning life in the orchard.”

O’Brien has achieved 80 percent success in re-growing frozen Reed avocado plants. 80 revived avocado plants are now growing in a glasshouse, the first time the plants had experienced life outside the laboratory.