Carleton Professor Helps Maple Syrup Producers Solve Mould Problem

By Liam McPherson

Maple syrup has been a Canadian staple for centuries and although many food-manufacturing processes have become automated, maple syrup is still largely made by small producers and bought from roadside stands and markets.

The Ontario Maple Syrup Producers Association (OMSPA), which represents more than 600 producers across the province, noticed there was a problem with this value chain. After receiving a large number of complaints about mould in maple syrup,­ OMSPA called in Carleton Chemistry Prof. David Miller — an expert on fungi and fungal toxins in food — to see if he could crack the sugary conundrum.

With an ENGAGE grant from the Natural Sciences and Engineering Research Council of Canada to produce “a sound scientific assessment of the conditions leading to fungal growth in maple syrup produced from a representative cross-section of producers in the region,” Miller was able to discover what was wrong.

For one thing, too much maple syrup was being sold with low sugar content that wasn’t compliant with Ontario regulations. This was due to a combination of lack of training and the use of old instruments that had not been calibrated for a very long time, as well as the accuracy of the various instruments used in sugar bushes. Ensuring the sugar content is correct reduces the risk of mould damage.

In July, Miller received an award of merit from OMSPA for his dedication, service and commitment to the province’s maple syrup industry. “We have learned from you and your work,” OMSPA past president and maple syrup producer, Ray Bonenberg, wrote in an email to Miller, “and we are trying to make our industry better.”

“I’m proud of it,” says Miller. “Nothing is more Canadian than maple syrup. It was small research project, but it had an impact that mattered to producers a lot.”

In addition to producing syrup with low sugar content, Miller found the method some producers were using to pack maple syrup was leaving their product with a greater chance of developing mould by the time it hit store shelves.

“There are two ways you can bottle maple syrup,” he explains. “There’s the ‘good way,’ and there’s a way that people use because it’s convenient if you’re a small producer. The latter method, which is called ‘cold packing,’ is more prone to post-consumer mold damage than ‘hot packing,’ which entails doing it in a continuous process.”

The amount of water a food contains is one of the biggest factors behind mold growth. “Things that look like Jell-O, for example, or jam, which are both semi-solid foods, one of them has a great deal more water than the other,” says Miller. “The fungi that will therefore grow on jam or high-sugar things are very special. So, generally, we don’t normally have a big problem with foods that have lots of sugar in them, unless they’re stored badly.”

Recent changes in Ontario’s training courses for maple syrup producers have been a positive step for the province’s industry, according to Miller. “It’s a fairly big business in Canada. Although Quebec produces most of the world supply of maple syrup, in Ontario, it’s about $65 million a year, and this is $65 million for farmers, not supermarkets — so it really matters to them.”

Maple syrup producers in the United States and other Canadian jurisdictions have become aware of Ontario’s change, says Miller, and it’s influencing their production methods, too. Questions about the fungi that occur in maple syrup and how sugar content is measured had not been looked at for more than a century.

Miller was especially pleased with the co-operation of the producers he worked with as he analyzed problems with their methods.

“They’re very proud of their product,” he says, “so it was quite a big thing for them to essentially volunteer it.’’

The maple syrup project is not a central part of his research, says Miller, but it shows “how science is used to make evidence-based decisions on regulation,” and “it reflects my perspective on public service and protecting rural people from needless economic harm.”

The work was published in the International Journal of Food Microbiology.