Research looks at apple rot

An apple a day may keep the doctor away, but the mold on it could make you sick.

Rhiannon Wallace, a PhD candidate at UBC Okanagan’s campus, has developed a way to stop, or at least control, blue mold—a pathogen that can rot an apple to its core. Wallace’s research has determined that bacteria, originally isolated from cold Saskatchewan soils, may be the answer to preventing mold growth and apple rot while the fruit is in storage or transport.

“The majority of postharvest fungal pathogens are opportunistic,” said Wallace, who is working with Louise Nelson, a UBC biology professor.

“If a fruit is physically damaged, it is at an increased risk of rotting during storage. So a tiny blemish on the fruit from harvest or handling can turn into a conduit for attack by fungal pathogens and subsequently result in the development of mold.”

The fungal pathogen penicillium expansum, also known as blue mold, destroys millions of stored apples each year. Post-harvest rot can result in yield losses of up to 20 per cent in developed countries such as Canada, while developing countries can lose up to 50 per cent of the crop.

The goal of Wallace’s research is to reduce the amount of produce lost due to post-harvest blue mold. Traditionally, post-harvest rot has been controlled with chemical fungicides, but Wallace says these treatments have become less effective as the pathogen has developed resistance and there is consumer pushback to the chemicals. The research by Wallace and Nelson aims to provide a safer and more sustainable alternative to fungicides.

Wallace suggests the solution may lie in a particular bacterium specific to Saskatchewan soil. Pseudomonas fluorescens, due to its Prairie roots, can survive in cold storage—a characteristic that is key to dealing with cold-stored produce like apples.

During tests conducted at the B.C. Tree Fruits Co-operative storage facility in the Okanagan, Wallace determined that these bacteria can prevent blue mold from growing on McIntosh and Spartan apples while in storage. In addition, during these experiments, the bacteria provided control of blue mold on apples that was comparable to a commercially available biological control agent and a chemical fungicide.

“What is novel about our research is that we show the bacterial isolates we tested have an array of mechanisms to inhibit or kill Penicillium expansum (blue mold) on apples while fungicides generally act only by a single mode,” Wallace says. “These findings suggest that the development of resistance by blue mold against our soil bacteria is unlikely.”

She does note that while all three isolates of P. fluorescens tested provided control of blue mold, the level of control provided by each isolate varied with apple variety.

Wallace’s research, supported by the Canadian Horticulture Council and Agriculture and Agri-Food Canada, was recently published in the journal Postharvest Biology and Technology. Further support came from the B.C. Tree Fruits Co-operative and Agriculture Canada’s Summerland Research and Development Centre.

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

Chilliwack on the map for Salmon Arm Roots and Blues

Canadian music legends confirmed for 28th annual music festival

Priest Camp near Summerland was created in 1845

Agreement formed between Grand Chief Nicola (1793-1859) and Father Giovanni Nobili (1812-1856)

Princeton snow removal costs top $40k in December

Costs of snow removal to the Town of Princeton skyrocketed in December.… Continue reading

Province says it is monitoring AIM’s road maintenance

The provincial transportation ministry is working closely with new road contractor AIM,… Continue reading

Princeton – a Prince Town in waiting?

The Town of Princeton has been waiting 160 years for a Royal… Continue reading

VIDEO: Bobcat infiltrates Shuswap couple’s coop, feasts on fowl

Police officers credited for attempting to assist with animal’s extraction

Local Lizzie: Be kind, always

Lizzie Skelton is a UBC Okanagan student who writes a column for Black Press

Power lines cut as thieves strike Vancouver Island veterinary hospital

‘Thankfully there weren’t any animals or staff in the clinic when this happened’

Summerland Steam earn two weekend wins

Junior B team defeats Osoyoos Coyotes and Kelowna Chiefs

Morning Start: 3D printed steak? No way…

Your morning start for Tuesday, January 21, 2020.

Alberta man dies in vehicle incident on Trans Canada Highway

The collision occurred Jan. 20, closing the highway east of Revelstoke till 1:30 a.m.

Skier dies at Fernie Alpine Resort

It’s the second person to die in a tree well at a ski resort in B.C. in the past week.

VIDEO: B.C. mom shares ‘insane’ experience of viral dinosaur video

Tabitha Cooper filmed her costumed sons meeting their grandma at the Victoria International Airport

Most Read