The true impact of Canadian milk packaging
Master of Environmental Studies graduate Alexander Cha challenges assumptions about single-use plastics.
Milk is a cornerstone of Canadian diets and a regularly purchased item at the grocery store. While packaging for milk and milk substitutes varies, most options rely on single-use plastics. The durability, low weight, and low cost of single-use plastics have popularized their use in food packaging. However, with consumption rates of single-use plastics growing, and the plastics industry being a notable contributor to greenhouse gas emissions, there is increasing concern about the negative impacts of these items on our environment.
Alexander Cha, a recent graduate of the Master of Environmental Studies in Sustainability Management, saw an opportunity to explore how packaging choices perform in a Canadian-specific context. After completing his undergraduate degree in Environment, Resources and Sustainability, Cha wanted to increase his competency in life cycle assessment in a program that values interdisciplinary thinking. Under the supervision of Dr. Goretty Dias, his master’s thesis quantified the environmental impacts of various milk packaging options being used in Canada, including paperboard cartons, plastic jugs, single-use and reusable glass bottles. Cha assessed the environmental impacts of these items under current conditions, and under the net-zero electricity grid Canada hopes to achieve by 2050.
Cha’s findings show that over the life cycle of milk packaging, the production stage has the largest environmental impact. Lightweight flexible plastic milk bags performed the best across most impact categories, while single-use glass exhibited the highest environmental impacts. Reusable glass packaging shows improvement with increased reuse, but the inclusion of sanitation and transportation adds to the overall environmental impact. Reusable glass packaging was identified as a competitive alternative to single-use plastics under ideal reuse infrastructure and a decarbonized electricity grid.
“Glass is a good example of why sustainability can be more complicated than it looks. The bottle may be reusable, but it is also heavier, which means more energy is needed to produce and transport it. It also has to be collected, washed, refilled, and reused enough times to make those added impacts worthwhile. If the bottles travel too far, are not reused enough times, or require too much energy and water to clean, the benefits of reuse can become much smaller.”
The results may seem surprising, but Cha cautions against categorizing all plastic as bad. “The most responsible approach is usually to reduce unnecessary consumption first, choose products with efficient packaging systems, and make sure the packaging is compatible with your local recycling or recovery infrastructure. End-of-life management matters just as much as the material choice itself.”
Cha’s master’s research provides a rigorous and Canadian-specific assessment of single-use and reusable milk packaging systems, contributing to the broader literature on sustainable packaging. The findings support moving away from material substitution as a default approach, and instead toward approaches that reduce packaging mass and improve circular performance. With stronger policy incentives or consumer demand for lightweight, recyclable packaging, environmental impacts could be significantly reduced.
Cha now works at Cleanfarms Inc., where he works closely with members and stakeholders across the agricultural sector on stewardship programs and extended producer responsibility. His time in graduate studies strengthened his ability to approach environmental challenges critically and communicate complex information in an approachable way.
Cha’s thesis, Life Cycle Assessment of Milk Packaging in Canada: Evaluating Reusable Packaging under prospective Energy Grid Scenarios, is available on UWSpace.
