There’s more to milk than meets the eye

KATE RYAN talks to dairy scientist, Professor Alan Kelly of UCC’s School of Food and Nutritional Sciences, as she continues our series on Milk
There’s more to milk than meets the eye

Professor Alan Kelly, School of Food and Nutritional Sciences, UCC, author of Molecules, Microbes and Meals book

FOOD? “Everything is chemical,” says Professor Alan Kelly. “Salt, sugar, alcohol, and vinegar are all chemical preservatives.”

It’s a painfully logical, inarguable and factual statement that has the power to trigger an enormous range of emotional responses.

Chemicals, chemistry, processing and processed are all terms that are incredibly loaded when we talk about food, he says.

“Particularly the term: Processed.”

“As a food scientist, my research and interest are in how we can transform food — which is the definition of processing to me. How do we make it safer, more stable, nicer, more palatable; how do we make it more affordable? It’s all the things we do, whether its heating, drying, fermenting — all of the operations we apply to the raw material, and the one that often gets left out is the need to make food safe to consume. That to me is what processing is.”

We consider milk to be a natural food product. And it is, but it is also a processed food.

Pasteurisation, the heat treatment applied to render milk safe and increase shelf life, is a processing treatment. As is the transformation of milk into butter, cream, cheese or yogurt.

Workers at a dairy factory making cheese. Picture: Stock
Workers at a dairy factory making cheese. Picture: Stock

“Let’s not demonise the concept of processing,” he says, a position that generated some considerable heat in 2019 following an article published for The Conversation.

But Professor Kelly’s point of view consists of far more than the sterility of data and numbers often associated with science.

“Science isn’t something to be wary of, to dissociate or view with suspicion: chemistry isn’t a four-letter word when it comes to food. Food is alive, food is biological, food is complex, food is chemical, cooking is chemistry and that’s alright!”

Hailing from the northside of Dublin, an area where cows and grass are relative strangers, Alan studied his undergraduate degree in biotechnology at what is now DCU.

“It was about the technical applications of biology (proteins and enzymes), using biological processes to make interesting products. It covered all kinds of areas — food was one of them.

“Food is one of the oldest applications of biology because every food system is a biological system. I was drawn to food and dairy because I liked the idea of working on something new, that was scientifically interesting, challenging and complex, but was applied and where the significance of research could be seen immediately.

“Food science is the science discipline where the gap between fundamental and applied is the shortest. There’s no other field of science where you can do research in a lab and literally within a matter of days or weeks see it having an impact in product improvement or a new product appearing on the shelves.

“To me, that made food science really interesting and fast-moving.”


After finishing his degree, Alan worked short spells in the brewing and dairy industries. Both experiences helped identify an area of interest to specialise in: dairy.

“I was working with a lot of UCC dairy science graduates and they said: If you want to study food and dairy, the only place to go is UCC. So, I went back to college to work on my PhD.”

His undergraduate studies in proteins and enzymes shaped his PhD research in understanding relationships between changing factors of milk, namely: the seasonality of milk production, grass quality and the bovine lactation cycle, and the ability to make products like cheese all year round to a consistent standard of taste and texture, despite these variances.

Close-up of large milk containers on a dairy farm.
Close-up of large milk containers on a dairy farm.


In 2004, the newly titled Professor Alan Kelly began his career at UCC at the university’s prestigious Dairy Science faculty.

In addition to teaching and research, he is an author of several books that aim to bridge the gap between the science community and a wider community of interest.

“There’s a dichotomy that exists between food as science and food as art. This idea that if it comes out of a factory it’s bad but if it comes out of a kitchen its good. We need to acknowledge that those issues are there, but by having a conversation about it, we can demystify some of the terms and ideas so that we can rapidly get to some sort of mutual understanding.

“That’s what I’m trying to achieve in general through my writing, to introduce a little bit of balance into the discussion. That was what was at the back of my mind when I wrote my books Molecules, Microbes And Meals And How Scientists Communicate.”

But what do we really know about dairy?

“Dairy is pre-science, it’s ancient science, people have been making butter and burying it in bogs for thousands of years! We have always known how to do certain things, but how and why do they work and how can we do them better is where science comes to the fore.

“For me, there is still plenty we don’t know about milk, plenty of areas ripe for research. We’re not coming to the end of dairy research by any means, and many research areas are concerned with breaking down milk and extracting things in different ways. How they can be applied, what are the really beneficial parts of milk and how can we make them better: breaking down the relationship between science and nutrition.”

There are interesting advancements in processing technology, too. Heat as a processing treatment is relatively crude, and we know from our general dislike for UHT (Ultra High Temperature) milk the significant changes to how palatable a food is after heat treatment.

But a novel process called High-Pressure Processing, or Cold Pressed as it is sometimes more commonly known, has been found to deliver on the safety and stability of a product like milk (it has even been used to halt maturation of cheese), but more importantly it doesn’t affect the taste.

“In dairy, the science is trying to catch up with the art. So, where do Novel Processes come in? One of the factors about processing, bearing in mind the public perception, is that in the past, processing has been a fairly blunt instrument: throw loads of salt or sugar into it, or heat it to an extremely high temperature because there wasn’t a scientific understanding. 

"We knew we had to do certain things to make it safe, but now there’s more subtlety in the understanding of how to do it.

“So, we can ask: are there different approaches that can be used? Are there different processes that can be applied that gain a high quality and acknowledges the consumers desire for naturalness, less processing and less change from the original taste of the food?

“There’s a growing market in Ireland for raw milk, but it’s a hazardous product if not handled right. In Australia, they’re utilising High-Pressure Processing instead of heat. The milk is then sold commercially as ‘Cold Pressed Raw Milk.’ Technologies such as High-Pressure Processing deal with the bacteria issue but don’t alter other effects on quality and give the impression of minimal processing.”

But beware: Cold Pressed refers to high-pressure processing but is also an extraction method — two different processes. The equipment is expensive and relatively small scale, lending this processing method to high value products rather than a bulk commodity, like every-day milk.

An essential part of Cork’s dairy industry are the processors. The county has a huge concentration of companies processing milk into butter and cheese, also ingredients such as protein powders, whey spirit distillate and infant milk formula. Carbery (who have just completed a €78m development of their plant in Ballineen), Kerry, Dairygold and Glanbia are Cork’s ‘Big Four’ processors.


Academic research requires funding, and in Ireland dairy science research is supported with both public and private funding.

The results of research inform the industry as well as increasing the academic breadth of knowledge. The close working relationships between academia and industry are quite unique to Ireland, says Professor Kelly.

“We have a close relationship with our dairy processors in academia, which is a strength of the system, yet it brings challenges and has to be managed. UCC are producing up to 50 food science graduates and post-graduates a year who are largely going into careers in the dairy sector, so that closeness is inevitable.

“It’s a buzz for me as an educator to seeing just how many of our graduates work in the industry, to see what they’re doing and where they’re going. 

"Dairy Sciences in UCC were established to provide qualified people for a growing dairy sector, and that’s what we’ve continued to do.

“There’s a three-way partnership in Ireland’s dairy industry: academia, industry and Teagasc - one of the largest dairy research centres in the world. The Irish government for many years has had a priority for funding applied for economically beneficial research. Dairy ticks that box very strongly in that its such a big part of our native economy: our three biggest sectors are ICT and Pharma-biotech (usually U.S multi-nationals based in Ireland), and Food made up of Irish-owned and Irish-born companies who are world contenders. There’s huge political pride in the success of the Irish food sector.

“A lot of money is put into dairy research, but what’s really important to do, and continue managing to do as a university, is to retain our independence; our function as educators and providers of knowledge and research.

“You don’t want the university sector in Ireland to become an outsourced R&D for industry, but keeping our independence while continuing to contribute, support and work with an economically important part of Ireland’s industry, while retaining the right to publish our own work.

“The Irish dairy sector is underpinned by a successful research structure, and there’s a mutual interest in making sure that the science quality remains high.”

The dynamism of the dairy sector is what continues to fuel Professor Kelly’s enthusiasm for research and teaching.

“Milk and dairy are hugely complex. For someone like me who has been interested in science their whole life, what keeps dairy fresh and interesting is its complexity and the challenges to be solved, and I think it excites our students as well. 

"We take food for granted in many ways, something that’s there, ‘un-sciencey’ or a bit basic; but it’s not. It’s challenging, important and hugely rewarding. Food is the most complex scientific thing we do in our lives every day, other than being alive. There’s more to food than meets the eye.”

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