A grocery store milk and dairy case lined with various milk and cream products. A sign at the top of the fridge says Simple, healthy and wholesome
Milk and dairy products in a grocery store display case. Photo: Yvette d’Entremont

If you regularly consume milk, chances are you don’t give much thought to the environmental impact of the container as you place it in your grocery cart.

But Mary Anne White has thought about it, and her research into the issue has forever changed the way she buys milk.

It has also made the Dalhousie University chemistry professor emerita passionate about sharing the news that pillow pouches (milk bags) are far better for the environment than jugs and cartons.

In an article published online in the Journal of Cleaner Production on November 21, White and three of her graduate students conducted life-cycle analyses of all three containers. They assessed the environmental impacts of each in Halifax and Toronto, examining energy inputs, greenhouse gas emissions, water consumed in production, and the transportation and disposal of each container.

They determined that milk bags consume only 20% to 30% of the energy, use 2% as much water as cartons do, and 40% as much water compared to jugs.

The bags also produce 20% to 40% of the greenhouse gases that jugs and cartons produce.

Bagged milk in a grocery store display case. Photo: Yvette d’Entremont

“I think we should all be aware of all our consequences on the environment of things that we’re doing on a daily basis,” White said in an interview. “What I’d like people to take away from this is to realize the consequences.”

Even if jugs and cartons are recycled and milk bags wind up incinerated or in a landfill, they still come out on top.

“The real key is how little material it takes to hold the milk in a milk bag compared to a jug or a carton,” White said. “It’s amazing that you could hold four litres of milk with 24 grams or so of material.”

The average Canadian drinks about 65 litres of milk each year. If an average household switched to exclusively using milk bags, the amount of energy saved each week would be equivalent to the consumption of one load of laundry in a clothes dryer.

While she frequently bought bagged milk before the study, the results led White to immediately make the switch to only bagged milk.

“I even reuse the milk bags. I wash them out, and they’re great freezer bags,” White said, cautioning that if you don’t frequently drink a lot of milk, then bags aren’t the answer.

“The milk will spoil before you get a chance to use it and then you’re wasting more energy associated with the preparation of milk you didn’t actually need.”

Dalhousie University chemistry professor emerita Mary Anne White. Photo: Milos Tosic

White hopes people also consider buying the largest container possible based on their milk consumption, noting the environmental impact of buying a couple of two-litre receptacles is greater than getting a single four-litre container.

“We can push for changes,” she said. “We don’t have one litre milk bags here, and if we did people who only need one litre could be doing that and they could be reducing their footprint associated with milk consumption.”

White said consumers in western Canada don’t have the option of buying milk bags at all as they aren’t available. That’s why she was pleased to learn the Western Dairy Council plans to discuss the issue at an upcoming meeting.

“If just in western Canada we could switch people to milk bags from jugs and cartons, we can save up to 5,000 tonnes of plastic annually,” White said. “That’s not insignificant.”

Although the study didn’t look at reusable glass bottles, White said they are only “potentially as good” as jugs or cartons. She said the energy used to make them, the fact they can only be reused a certain amount of times, and the cleaning and sterilizing required in between uses has a significant environmental impact.

“If we could just get people thinking about what goes on behind the scenes. You just grab your milk off the shelf, out of the fridge, in the grocery store, and it’s always there and available,” she said.

“And that’s just the packaging. If you think about the milk too, food waste is another huge thing…We are very wasteful in this country, and we should just be a little bit more careful about our thinking on all of that.”


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Yvette d'Entremont

Yvette d’Entremont is a bilingual (English/French) journalist and editor, covering the COVID-19 pandemic and health issues. Twitter @ydentremont

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3 Comments

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  1. I find these kinds of stories interesting. They’re of the genre of “here’s a little thing you can do that if everybody did it we’d all be living in an environmental and social justice paradise”
    I ride my bike to work (primarily for reasons of climate change and have been doing so for 25 years. I reduce, I reuse, I recycle as much as I can, I have solar hot water panels. BUT, I still fly places, I still own a car, I still have an oil furnace.
    The point is that emphasising the things that individuals can do to ameliorate the effects of being a human living in a country with one of the highest carbon footprints per capita in the entire world, is to completely miss the point of the systemic problem that exists and that I as an individual have exactly zero power to change.
    I am not writing this comment to disparage this article at all. In fact I will probably look at changing the way I buy milk although 4 litres for our family of three may be excessive as mentioned in the article. I am just writing this to bring attention to the fact that individual acts may make us feel better but we should be under no illusions that they do jack-squat to actually address THE existential threat that is the climate catastrophe that we are already undergoing.

    1. HRM is keen to fight climate change….but allows bars and restaurants to use patio heaters ! And is keen to have more tourists flying into the province.
      Go big or stay home, and keep on virtue signalling.