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.

Just Posted

Penticton Vees erase two-goal deficit to defeat Trail

The Vees take Game 1 of the second round of the BCHL playoffs

2.5 years in Penticton courthouse over neighbour assault ends

Man pleaded guilty, withdrew, stood trial, pleaded guilty to assault described by Crown as ‘vicious’

UBCO civil engineer touts cohousing option

Gord Lovegrove says cohousing is sustainable social and economic lifestyle

Country star takes a dip for charity

Brett Kissel went for a dip in Okanagan Lake while in Penticton to raise money for Her International

Pursuit of Excellence defeats OHA in female prep hockey final

Okanagan Hockey Academy lost to Pursuit of Excellence 6-3 at the CSSHL final in Penticton

Sharing the voices of the mountains with Spirit North

Celebrating the first season of the Spirit North ski program for Indigenous youth at Nickel Plate

How to keep local news visible in your Facebook feed

Facebook has changed the news feed to emphasize personal connections. You might see less news.

BCHL Today: Wenatchee Wild goaltenders a cause for concern

BCHL Today is a (near) daily look at what’s going on around the league and the junior A world.

Canadian survivors, supporters rally against proposed ’60s Scoop settlement

Some have accused the government of underestimating the number of survivors

Nordic athlete Arendz to be Canada’s flagbearer at Paralympic closing ceremony

The biathlete and cross-country skier from Hartsville has raced to five medals in Pyeongchang

Salmon Arm community cheers on Natalie Wilkie as she wins first gold medal

Local skier tops the podium in 7.5km race at the PyeongChang Paralympics

Experts: Society has a role in trying to prevent domestic violence

Experts are speaking out following the murder of a woman and her son in Ontario

Progress on fixing Phoenix pay system backlog could be short-lived: Ottawa

Feds have said they won’t try to recover money overpaid until all outstanding issues are fixed

Most Read