Cleaning chlorates out of dairy processing

Research Lives: Dr Billy McCarthy, post-doctoral researcher with Teagasc

Prof Pat Guiry, Royal Irish Academy president, with Billy McCarthy (centre) winner of the 2024 Kathleen Lonsdale RIA Chemistry Prize, and Christine O'Connor, head of environmental health and safety management at TU Dublin.
Congratulations, you recently won the Kathleen Lonsdale Royal Irish Academy Chemistry Prize for your PhD — what was your project about?

I was a Walsh Scholar at Teagasc, and my PhD at Moorepark and TU Dublin looked at how chemicals called chlorates can make their way into dairy products through food processing systems, and what to do about it.

What are chlorates?

Chlorates are breakdown products from substances such as bleaches used as cleaning agents during water treatment. They can cause health issues if the concentrations are too high, so there have been steps to regulate and remove them from food processing systems.

What did your project find?

I found that chlorates could be introduced into dairy processing mainly through chlorinated water. If that water was then used to operate equipment like spray dryers or evaporators, chlorates could possibly make their way into the system.

Were you able to identify ways to stop that?

Yes. I came into my PhD from a background in pharmaceutical chemistry, and looking theoretically at the problem of chlorates in food processing I had grand ideas of what could be done.

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But very quickly I learned the difference between what would be nice to do and what is possible and feasible. So for the PhD I focused on existing processing systems in the dairy industry and what was in the power of the processor to do to combat the issue.

I found that you applied membrane filtration at different points along the process, which would lead to better results downstream. What’s nice about it is that people are already trained in this kind of membrane processing, it is already in use, so it’s now a case of applying it at critical control points.

What kind of impact does this information have?

Dairy processors are now using what I found in my PhD to make changes, so they are applying the membrane filtration to take the chlorates out, and in the case of spray drying to make powders, they are treating water with reverse osmosis to remove chlorates.

What sparked your interest in science?

I was always interested in science at school in Midleton in Cork. I did a project on plastics with a friend for the BT Young Scientist & Technology Exhibition and we won third place in our category, then I worked with my science teacher to set up a club to help other students who were interested in doing the Young Scientist.

Also my Dad worked in the pharmaceutical industry and he always encouraged my curiosity when I was questioning things. I studied biological and chemical sciences at University College Cork, and I specialised in the chemistry of pharmaceutical compounds.

What have you been doing since you finished the PhD?

I’ve been working as a postdoc at Teagasc, looking at different kinds of whey proteins that cows produce. My work has been evaluating how they affect biological processes, with a view to identifying which ones could be used as health-promoting ingredients.

And how do you take a break when you are not working?

During my PhD I enjoyed setting up a monthly social event in Cork called PubhD, where postgraduate researchers from across different disciplines get to present informally about their work for 10 minutes. And since my PhD finished, I have been really enjoying falling back in love with reading for leisure. I’m currently working my way through Game of Thrones.

The Kathleen Lonsdale RIA Chemistry Prize, sponsored by Henkel, is awarded for outstanding doctoral research in the chemical sciences carried out on the island of Ireland

Claire O'Connell

Claire O'Connell

Claire O'Connell is a contributor to The Irish Times who writes about health, science and innovation