Your compost bin could be a plastic factory

Here is something that has been thoroughly categorized by scientists all over the world, and has been used in a variety of applications: bacteria.

Here are two problems: food waste and plastic pollution.

Here is a solution: Bacteria that feed on food waste and have a product of usable plastic.

It may seem like a fantasy, but scientists have been developing sustainable methods of using endogenous pathways inside bacteria that produce plastics from carbon sources. With food waste being well documented as a significant portion of all landfill waste, and plastic production contributing largely to global greenhouse gas (GHG) emissions, diverting food waste to controlled microbial processing facilities will address two problems at once.

Some bacteria can produce a diverse group of plastics known as Polyhydroxyalkanoates (PHA) as a by-product of their regular metabolism (Nielson et al. 2017). This plastic is bridgeable, can be easily moulded into different products, and is a thermoplastic, which means it does not interfere with the recycling process if it is thrown into a blue bin rather than a green bin (Campbell 2019). Luna Yu is a researcher at the University of Toronto who is working to perfect this technique. She specializes in creating PHAs through her start-up Genecis that are used for high-end products such as 3D printing filament, flexible packaging, and medical equipment.

Current hindrances of this process have included the cost of viable carbon sources, which compromised 28-50% of the total production process (Nielson et al. 2017). Although food waste may intuitively be the best carbon source, its composition is often too impure to feed to the PHA-producing bacteria directly (Nielson et al. 2017). Straight food waste must first be pre-treated and processed into basic compounds like simple sugars and fatty acids, which can then be used by bacteria to produce PHAs (Nielson et al. 2017). This process, however, can also be done through genetically engineered bacteria as opposed to using laboratory chemicals (Campbell 2019).

Stressors such as nitrogen and phosphorus starvation are often needed to induce the PHA-producing mechanisms, which adds layers to the work needed for this process to work (Nielson et al. 2017). Using synthetic biology and engineering, however, this system can be hijacked so that the bacteria can constantly produce PHAs (Nielson et al. 2017). A specific strain of Escherichia Coli, the standard organism used in genetic engineering, has been modified to contain A. latus genes that create PHA (Nielson et al. 2017). This strain of E. Coli can produce a dry weight of 80.5% PHA to the weight of a single cell, which means 1kg of dry bacteria would yield 805g of plastic, for example (Nielson et al. 2017). In their paper, Nielson et al. (2017) present a table outlining various combinations of food waste categories, kinds of PHAs that are produced, and the bacterial genes responsible for them.

With future advancements, it could be possible that the technique of converting food waste into plastic could be integrated into modern households. Plastics are a commodity that has become abused and overused to the point where today people cannot envision a world without a plastic grocery bag or disposable utensils. Not only do plastics often pollute our environment and oceans, but their production also involves using oils and natural resources that pollute the earth even more. Investing in synthetic biology to produce bridgeable plastics can change resource use in more ways than one.


Campbell, D. U of T startup that turns food waste into high-quality bio-plastic eyes next phase of growth. University of Toronto News. Posted 24 September 2018. Accessed 12 June 2019. Available from:

Nielsen, C., Rahman, A., Rehman, Rehman, A. U., Walsh, M. K., Miller, C. D. Food waste conversion to microbial polyhydroxyalkanoates. Microbial Technology. 10(6), (2017).



A Chicken in Hand is Worth Ten Apples in the Bush

How many bags of compost do you generate in a week because your food went bad? One or two? But how about supermarkets? Every time you buy food, you may look for the items that look freshest. The one with the furthest expiry date. Most firm. Most ripe. Most pretty. You are not the only one that seeks these characteristics in the food products you buy, so what happens to the food that gets left behind? Once food items become spoiled to the point that supermarkets have deemed they will not be bought, they become waste.

Between six supermarkets studied in Sweden over a three-year period, 1570 tonnes of food waste (excluding bread) was generated (Scholz et al. 2015). Comparatively, the average person in Sweden generates 72kg (0.072 tonnes) of food waste each year. Scholz et al. (2015) analyzed the mass composition and ratio of annual supermarket waste and found discrepancies between the number of food items wasted per category, and their relative greenhouse gas emissions. Results showed that while fruits and vegetables comprised a whopping 85% of food waste by mass, they only contributed to 46% of the wasted carbon footprint (Scholz et al. 2015). As for meat products, they only contributed to 3.5% of the wasted mass but 29% of the total wasted carbon footprint (Scholz et al. 2015).  

In addition to the environmental impact, Brancoli et al. (2017) also state that meat waste contributes more to a supermarket’s economic loss than produce. One technique to reduce meat waste is outlined by Eriksson et al. (2016) whereby reducing storage temperature results in lower quantities of waste. Eriksson et al. (2017) described that changing the storage temperature for deli products from 8˚C to 5˚C results in 15% less food waste. They also point out that minced meats, which are often stored chilled, could be kept frozen to reduce their wastage as well. For produce, the authors categorized the main contributors to still be fresh, edible, and have a high quality (Scholz et al. 2015). This wastage is likely due to supermarkets often providing 7% more food than expected as customer demands can be difficult to project, and as newer and “better” products replace old, although still edible, ones (Brancoli et al. 2017). 

Supermarkets do have tools to reduce their food waste. Keeping foods frozen and at different temperatures, and possibly purchasing less, are small steps that could make big a difference.


Brancoli, P., Rousta, K., Bolton, K. Life Cycle Assessment of supermarket food waste. Resources, Conservation and Recycling. 188, 39-46 (2017).

Eriksson, M., Strid I., Hansson, P. Food waste reduction in supermarkets – Net costs and benefits of reduced storage. Resources, Conservation and Recycling. 107, 73-81 (2017).

Scholz, K., Eriksson, M., Strid, I. Carbon Footprint of Supermarket Food Waste. Resources Conservation & Recycling. 94, 56-65 (2015).

Alternatives to the Composter!

Food waste occurs from parts of food that we deem to be waste, but in some cases, we can do something with those off-casts. Below is a list of food items I see others commonly throwing in the composter, but that I as a home chef have found other ways to use.

Baked Broccoli and Cauliflower Stems Recipe

  1. Chop stems into disks.
  2. Mix in some olive oil, paprika, garlic powder, salt, and pepper with the disks.
  3. Bake disks in the oven at 450˚F for 30 minutes or until crispy brown (this time could change depending on how big your disks are).

Fried Potato Skin Recipes

  1. Heat canola oil in a skillet about 1cm deep.
  2. Pat dry potato skins with a towel.
  3. Fry potato skins on oil until crispy and brown.
  4. Scoop out potato skins with a draining spoon and put onto a plate lined with a paper towel.
  5. Sprinkle with salt and serve.

Avocado Appetizers In Skins

  1. Ensure you have cut the avocado into two symmetrical halves, keeping the flesh as intact as possible.
  2. Dice the flesh.
  3. In a frying pan, heat olive oil and pan-fry the diced avocado with some salt and pepper.
  4. When crispy and golden brown, put the fried avocado into the skins for a fancy presentation, and garnish with salsa to-taste. Serve with spoons.
  5. I also like to use the avocado skins for individual guacamole.

Fruit Pulp Crackers

This is a recipe I found on OneGreenPlanet, but always works!

  1. Mix all of the ingredients below in a food processor, and thinly spread the mixture on a baking sheet:
    • 2 cups juice pulp
    • 1 tablespoon chia seeds
    • 1/2 cup flaxseeds
    • 3 tablespoons tamari
    • Dash of turmeric
    • 1 teaspoon dried oregano
    • Black pepper, to taste
    • 1/4 cup water, or a bit more to allow contents to mix in the processor
  2. Bake at 320˚F for 40-50 minutes and flip halfway through.

Flavoured Banana Peels
This recipe one I found on a youtube video. When I make it, I omit the cumin seeds and coriander powder because I find them overpowering.

  1. Dice one or two banana peels on a cutting board.
  2. Heat about two tablespoons of oil in a pan.
  3. Add in some fennel seeds, cumin seeds, and mustard seeds.
  4. Mix in the banana peels and add chilli powder, salt, coriander powder, and lemon juice.
  5. Continue cooking until the peels are reasonably golden brown and serve

Can Animals be Composters?

On my volunteering trip to a rural part of Panama, the compound at which my team stayed often had stray dogs that circulated the outdoor dinner table every night. We scared 3 or 4 different dogs away every time in fear of catching diseases they might spread, but we were puzzled as to why they kept coming back. On the last day of the trip, we found that our leftover food was being left outside every night for the dogs to feast on just meters away from the dinner table. 

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A stray Panamanian dog resting as she waits for us to finish our dinner

My team and I were shocked—in Canada, some individuals buy heavy-duty lockable trash bins or even go as far as tainting their garbage with poison to deter animals from getting to it. In Panama, they treat wild animals as part of their community. I wondered if it is because humans have a stronger emotional connection to dogs as opposed to raccoons. Or, maybe in North America we are too concerned with attracting pathogenically contagious vermin (a valid argument), and not consciously allowing our street to look “dirty”. Why are Panamanians not concerned like we are? In the previous trips I’ve been on to Central America, the cultures are often described as being much more “community-oriented” compared to the North; they have tighter relationships and interact more frequently with neighbours, and I argue that this strong sense of care to each other extends to the wildlife around them. Panamanians are more concerned with the well-being of the stray dogs in their community than the detriment to their health or aesthetic brought by the animals’ presence.

The United States Environmental Protection Agency describes feeding animals as the third tier in their food recovery pyramid, preceded only by source reduction and feeding other people. Click here to go to their website. Surprisingly, composting—the holy grail of mitigating food waste—is tier five of six on their pyramid, which puts into perspective how beneficial feeding animals our food scraps could be.

Am I suggesting you start a food scrap pile in your neighbourhood? 

No. The reality is, stray animals can still carry diseases, be nuisances, and maybe even be aggressive. Given the structure of some cities and towns, feeding animals might not be easy to do, and it is not always safe. Just because Panamanians have grown accustomed to this lifestyle does not mean it can be replicated everywhere. 

That does not mean, however, that your food waste should always be destined for the composter—which brings me to my second point. For the many of you that have pets at home, there is a large variety of foods that can be safely consumed by cats and dogs including certain meats, veggies and grains. Dogs specifically evolved alongside humans eating their leftovers, and it was not until the past several decades that industries began heavily marketing synthetic dog food. If you are unsure of what you can feed to your pets, you can always reference reputable internet sources or contact your local vet—it may save resources and your money.

Some Universities and institutions are even donating food scraps to nearby farms. Everyday, 1 ton the food scraps from the kitchens at Rutgers University go directly to the hogs and cattle of a nearby farm. The university only pays half of what it would to the city’s organic collection system, and the animals get to enjoy a healthy variety of food. If you live near farm, this extra step could be an option for you too.

Although it may not be ideal to live exactly like generous Panamanians, we North Americans can still learn from their lifestyle to reduce our food waste in an alturistic manner.

The Connection Between Food Literacy and Food Waste

Food literacy is considered by many in the world of food and nutrition to be an important strategy to enable healthy eating and reduce risk of obesity and chronic disease. Recent literature suggests that the positive impacts of improving food literacy may extend even broader, into the realm of food waste reduction. The question I hope to explore in this post is whether improving food literacy can assist with decreasing household food waste.

First and foremost, what exactly is food literacy?

Although an exact and commonly agreed upon definition is unavailable, food literacy is described by the Food Literacy Centre as “understanding the impact of food choices on one’s health, environment, and economy.”

Pertaining more specifically to food waste, Farr-Wharton, Foth & Choi (2014) define food literacy as “the degree to which past experiences and acquired knowledge impact a consumer’s food consumption and wastage practices.” Food literacy is ultimately the knowledge and understanding that we have of food and how it can be used to meet our needs.

Some would argue that when exploring ways to reduce household food waste, improving food literacy is crucial. The logic is clear, if consumers have a greater understanding of how food choices impact their health, environment and bank accounts, they would likely waste less food.

Let’s take a closer look.

Food waste occurs within many different yet interconnected practices of daily life, from shopping for and storing food to cooking and eating (Schanes, Dobernig, & Gözet, 2018).  Improved food literacy has been shown to assist with the development of cooking and eating practices that are less wasteful. Those who have a greater degree of food literacy are better able to plan meals, estimate portion sizes and cook more spontaneously, perhaps based on what items are left in the fridge – a practice that requires time, knowledge and cooking skills (Schanes, Dobernig, & Gözet, 2018). An essential part of food waste reduction is knowing how to creatively use up ingredients while cooking to keep them from going to waste – a practice that improved food literacy could certainly support.

It is believed that as a population, we have lost a great deal of both food literacy as well as basic cooking skills. It is possible that this decline has contributed to the current rise in food wastage.

Moving on to the second definition for food literacy above: how might past experiences influence wastage practices?

The answer is quite intuitive. Have you ever had a really bad experience with a particular food? Sour milk discovered mid-swig, mouldy cheese tucked into a sandwich or worse yet, a bad bout of food poisoning from a particular food? These kinds of negative experiences with particular foods can lead to taste aversions, over-sensitivities and repeatedly disposing of food prematurely “just to be safe”.

If food literacy is based both on consumers’ acquired knowledge and past experiences with food, interventions for both aspects should be implemented. So, what are some tangible effects we can have on food waste reduction through food literacy promotion?

Improving cooking skills is identified in a paper by Pearson, Mirosa, Andrews, & Kerr (2017) as an expert recommendation to reduce household food waste. Furthermore, work should be done to support positive experiences with food, especially early in life  (see: Rainbow Plate and The OHEA Food Literacy Initiative for some local examples). Finally, educating consumers about safe food practices to prevent negative experiences with food would also be helpful.

Ultimately, there is some evidence to show that improving food literacy could assist with household food waste reduction. However, this remains a relatively small “piece of the pie”. Food waste behaviours are motivated and influenced by each individual’s values, awareness, attitudes, household dynamics, lifestyle and convenience – among many other factors – making it a complex problem to solve. That being said, moving forward it could be useful to see more collaboration between those working to improve food literacy, and those working to reduce household food waste generation.


Pearson, D., Mirosa, M., Andrews, L., & Kerr, G. (2017). Reframing communications that encourage individuals to reduce food waste. Communication Research and Practice, 3(2), 137–154.

Schanes, K., Dobernig, K., & Gözet, B. (2018). Food waste matters – A systematic review of household food waste practices and their policy implications. Journal of Cleaner Production, 182, 978–991.

Farr-Wharton, G., Foth, M. & Choi, J.H. (2014). Identifying factors that promote consumer behaviours causing domestic food waste. Journal of Consumer Behaviour, 13, 393-402.

Tub or Tube?

I am sure we all know the irritating feeling of having food right in front of us and not being able to eat it, and then having to throw it away. 

But, let me be more specific—you are famished and holding a nearly empty tub of Nutella. Your spoon is just enough to reach the bottom, and the container is too small for your big hands to really have any autonomy over it. The more you scrape, the harder it becomes to fill your spoon. You enjoy any little bit you can manage to get on the tip of your silverware, but you know you will soon have nothing. And then it happens. In the midst of the adrenaline and hopefulness you had of having a fulfilling snack after a long day of work, you accept that you have lost the battle to the Nutella container and can’t get any more onto your spoon. As you lick the messy fingers of one hand, the other hand throws away a jar cumulatively containing at least a whole delicious spoonful of hazelnut spread into the garbage. A tragedy to your taste buds, but there is nothing else you could have done.

If containers like those of Nutella jars had been designed differently, maybe you would not have been left in sorrow wondering if you should have tried harder. Not only can it be a tough play on our emotions, inefficient food packaging is a considerable source of food waste. Nutella is not the only brand guilty of forcing us to waste food—peanut butter, condiments like ketchup and mayonnaise bottles, salsa jars, glass bottles of thick sauces like teriyaki, and even yogurt cups all leave behind dirty containers that often end up either down the sink or in a landfill. 

If you were to add up all the ketchup you’ve thrown away during you whole like from “empty” bottles, how many new bottles could you fill? One? Five? Food waste in landfills is a significant producer of methane, a greenhouse gas 30 times more potent than the infamous carbon dioxide.

Not all packaging favours food waste like the examples above. Yogurt tubes, freezies, and bagged milk allow you to perfectly squeeze out all the contents, popsicles can be sucked until only a compostable wooden stick is left, and butter wrappers perfectly peel off the block when it is cold enough. Trying to decide between a tasty treat and being conscientious of the environment can often require making sacrifices; without our continuous awareness of climate change, however, we might not be around for too long to be able to make these decisions.

It’d just be nice if they made tubed Nutella.


Shaping the Canadian food waste conversation

This blog post discusses our team’s recently published peer-reviewed article. For the full article, please visit this page.

As we have discussed in previous blog posts, food waste is now recognized around the world as a pressing environmental, social and economic issue. Although food waste occurs at all stages of food production and consumption, some estimates suggest that up to 50% of food waste in Canada is generated at the household-level. As awareness around food waste grows, pressure is building to develop effective and timely solutions.

However, evidence-based suggestions and high-quality food waste data remain relatively scarce. Without a solid foundation and understanding of food waste, how can we inform narratives that encourage consumer behaviour change? So far, there is little academic literature that systematically observes household food waste generation in a Canadian context.

Our interdisciplinary team from various departments across campus sought to fill this gap by conducting a study among families with young children living in Guelph, ON.

Study Overview

Throughout the study, all families were asked to keep track of every food purchase receipt – from grocery stores and farmers markets to restaurants and take-away establishments – anywhere that food was purchased. Throughout this period, we collected each families’ household waste including their recycling, garbage and organics. This waste was then audited by a team of very dedicated (and brave!) graduate students in the first year, and by a professional audit company the second year. Each individual food item was separated, recorded and weighed. All food items were also classified as being either avoidable or unavoidable. For example, a whole banana would be peeled, and the peel would be considered unavoidable, whereas the actual banana would be avoidable. Our focus was on the avoidable portion of food waste – any food that was at some point edible. In the end, we had 316 unique avoidable food items. It was this list that formed the basis of our subsequent analysis.

What did we find?

Overall, the average household in our study generated approximately 2.98kg of avoidable food waste per week. Fruits and vegetables made up two thirds of this waste, followed by breads and cereal making up about a quarter of total waste.

That being said, it can sometimes be difficult to visualize food waste in terms of a weight value. In order to further contextualize these results, we examined the dollar value, nutritional losses as well as environmental impacts of what was thrown away.

In our study, one week of avoidable household food waste represented…

3,366 calories.

This is the recommended daily caloric intake for 1.7 children or 2.2 adults. This means that the average household in our study could have provided an additional five adult meals, or 7 child meals based on the edible items they wasted. The items wasted also represented significant losses of fibre, magnesium, calcium, vitamin D, vitamin B12, vitamin C and vitamin A – all nutrients that are often consumed below recommended intake levels in Canada. Weekly wasted food represented 2.3 servings of fibre, 2.5 servings of vitamin D, 1 serving of vitamin B12, 4.8 servings of vitamin C, 1.9 servings of vitamin A, 0.9 servings of calcium and 1.6 servings of magnesium.

In this case, wasted fruits and vegetables represented a significant missed health opportunity.


An extra $18 a week in a family’s pocket could go a long way!

23.3 kg of CO2.

This equates to 1.2 tons of carbon dioxide which is equivalent to one quarter of the emissions from a car being driven for a year, or 2.8 barrels of oil consumed.

6.7 m2 of land and 5000 L of water.

Consider that the average 5-minute shower uses 35 liters of water. Wasted avoidable food items represent close to 143 showers per week!


What does this mean?

These multiple valuation frameworks provide different means of communicating the impacts of food waste to both policy makers and the public at large. Our hope is that these new perspectives, based on detailed observations of family food behaviours rather than estimations derived from system-wide data, will enable more informed and urgent conversations around food waste in Canada.

Article Reference:

von Massow, M., Parizeau, K., Gallant, M., Wickson, M., Haines, J., Ma, D. W. L., … Duncan, A. M. (2019). Valuing the Multiple Impacts of Household Food Waste. Frontiers in Nutrition. Retrieved from

#foodwaste #Canada #households #valuation #health #economic #environmental

Trash Talk Post 4: ‘Nudging’ Food Waste Reduction

‘Nudge theory’ is a behaviour change approach initially presented by economist Richard H. Thaler and Law Professor Cass R. Sunstein in their popular book “Nudge – Improving decisions about health, wealth and happiness”.

Thaler and Sunstein (2008, p. 6), describe a nudge as:

“any aspect of the choice architecture that alters people’s behavior in a predictable way without forbidding any options or significantly changing their economic incentives. To count as a mere nudge, the intervention must be easy and cheap to avoid. Nudges are not mandates. Putting the fruit at eye level counts as a nudge. Banning junk food does not.”

This “choice architecture” represents all outside forces that may subtly guide individuals’ decisions. Based on this theory, behaviours may be altered by changing the nature of this environment. This manipulation is called “libertarian paternalism” and is meant to improve people’s choices, and their associated outcomes, while also allowing individuals to maintain their freedom of choice.

This theory has been widely applied in nutritional research. Interventions that change the choice architecture of the subject, while maintaining their autonomy, have been developed and tested in order to assist consumers in making healthier food choices.

Given the overlap between food waste prevention behaviours and general food-related choices, it seems likely that nudge theory could also be used to prevent food waste generation at the household-level. The habitual and unreflective nature of food waste behaviours make them highly suitable for nudge-based interventions. However, before getting into this concept more, it is interesting to first consider some of the literature examining nudge theory and healthy food choices.

‘Nudging’ Healthy Food Choices

In a meta-analysis conducted by Arno & Thomas (2016), nudge strategies were found to successfully improve nutritional choices. Chandon and Cadario (2018) build on this concept further by categorizing and labelling the most common nudge interventions developed. Based on this analysis, nudges were broken down into three broad categories.

  1. Cognitive

Cognitive nudges work by providing consumers with information and trusting that they will use it to make better choices. An example of this could be making the healthy option more visible. This could be done by including calorie count or nutrition facts on a restaurant menu. These kinds of nudges can be further improved by adding some context, known as evaluative labelling, such as a smiley faces or traffic colours.

Although cognitive (also known as informational) nudges certainly have merit from an educational and ethical standpoint, they have been found to be only a quarter as effective as behavioural nudges.

  1. Affective

Affective nudges make more of an appeal to our emotional sides by making healthy food sound more exciting or appealing. Using either signs, displays or else verbal encouragement, consumers can be directed to make better choices. An example of this might be arranging an appealing display of fruits and vegetables.

These strategies were found to be moderately successful at improving food choices.

  1. Behavioural

The final category of nudge also happens to be the most effective at changing behaviour. Behavioural nudges work to modify behaviours without necessarily changing what people think or what they want. This method does not require any collaboration or volition on behalf of the individual. An example of this might be enhancements that make healthier options easier to eat – such as pre-cutting fruits and vegetables or perhaps modifying plate size.

Nudge-Based Food Waste Interventions

Can these same theories and types of nudges be used to reduce food waste generation at the household-level? Although research remains relatively limited in this domain, some studies have begun to answer this question.

In a study conducted by Kallbekken and Salen (2013) two simple, non-intrusive nudges were tested in their ability to reduce the amount of food wasted in a hotel restaurant. The first intervention tested was simple; a reduction in plate size offered at the buffet. Based on the above criteria, this would be called a behavioural intervention. Previous research has shown that this simple switch reduces portion size as well as subsequent food waste. The second nudge was a direct social cue in the form of a sign at the buffet encouraging guests to help themselves more than once. This was theorized to create the social norm that it was acceptable to revisit the buffet and thus would discourage people from loading too much on their plates at once. Both of these “nudges” relied on influencing consumption norms through external cues.

The results of these nudges were significant, a 20% decrease in food waste. Although these results suggest some promise, these types of nudge interventions would only be relevant in a context where buffet meals are served.

Another study conducted by Shearer et al. (2017) examines a nudge intervention at the household-level, but specifically in terms of food waste recycling, rather than food waste preventing behaviour.

In a randomised control trial, the effectiveness of using stickers as a visual prompt to encourage the separation of food waste was investigated. The study began with a 15-week baseline period where all waste streams were collected and weighed. Participants were then divided into control and treatment groups. In the treatment group, stickers encouraging source-separation of food waste were affixed to the lids of their waste collection bins. After 16-weeks of follow-up collection and weighing post-treatment, researchers found a significant increase in food waste recycling in the treatment group and no change in the control group. This change was found to persist long-term.

The authors conclude the article by suggesting that a small nudge in the form of a sticker prompt may have a sustained impact on food waste recycling rates. This is a simple, feasible and relatively inexpensive behaviour change intervention. However, one can argue that the behaviours required to prevent food waste, rather than divert it, remain quite different. Therefore, this kind of intervention may have less success in preventing household food waste.

Finally, a recent study conducted by von Kameke & Fischer (2018) takes a first exploratory analysis of the possibility of nudge interventions to reduce household food waste. Using a questionnaire, researchers sought to better understand consumers’ preferences and interest in changing their food waste behaviour. Results suggest that respondents were open to behaviour change and were interested in learning more about the topic. Authors use these results to indicate that nudging could be a suitable tool for reducing household food waste. However, they are unable to report on the actual efficacy of the nudging approach as no intervention was implemented.

Further research should build on these results by testing the nudging approach through intervention studies that measure actual food waste before and after the implementation of nudges

In summary, there is evidence to suggest that behavioural nudges may be the most effective at encouraging behaviour change and thus should be more thoroughly examined. However, based on the presented research the question remains; can nudges be effective at preventing food waste at the household-level?


  • Arno, A., & Thomas, S. (2016). The efficacy of nudge theory strategies in influencing adult dietary behaviour: A systematic review and meta-analysis. BMC Public Health, 16(1), 1–11.
  • Cadario, R., & Chandon, P. (2018). Which healthy eating nudges work best? A meta-analysis of field experiments. Appetite, 130, 300–301.
  • Kallbekken, S., & Sælen, H. (2013). “Nudging” hotel guests to reduce food waste as a win-win environmental measure. Economics Letters, 119(3), 325–327.
  • Shearer, L., Gatersleben, B., Morse, S., Smyth, M., & Hunt, S. (2017). A problem unstuck? Evaluating the effectiveness of sticker prompts for encouraging household food waste recycling behaviour. Waste Management, 60, 164–172.
  • von Kameke, C., & Fischer, D. (2018). Preventing household food waste via nudging: An exploration of consumer perceptions. Journal of Cleaner Production, 184, 32–40.

Trash Talk Post 3: Technology to Reduce Household Food Waste

This post was originally posted on FoodFocusGuelph and is part of a four part series on household food waste.


Human-Computer Interaction (HCI) or Human Machine Interface (HMI) is a growing area of research that has begun addressing issues related to ecological sustainability. Given the environmental impacts of food waste, some researchers have begun developing technologies that seek to reduce household food waste generation.

From fridge cameras to “smart” bins, a new era of food waste technology is emerging. However, prior to being implemented on a large-scale, it is important to assess and test these technologies with consumers. In this blog post, I take a look at three studies exploring new technologies designed to reduce household food waste.

Negotiating Food Waste: Using a Practice Lens to Inform Design 

Ganglbauer, Fitzpatrick, & Comber (2013) conducted a study to first better understand household food waste behaviours, and to then test a novel technology designed to reduce food waste. A relatively small-scale study, 14 households were recruited for interviews and house tours to observe and measure food waste generation. Next, 5 households had a fridge camera installed for one month to assess its ability to reduce food waste.

Dubbed the FridgeCam, this technology involves a mobile phone attached to the inside of a refrigerator door. For every second the fridge door is open, an accelerometer sensor in the phone triggers the camera and several pictures are taken and uploaded directly to a dedicated webpage. Users can then access the latest 15 captured photos either through their smart phones or on their computers.

Researchers expected the app to be most often accessed via mobile devices in order to allow users to access the information on the go – perhaps while shopping or meal planning. However, far more often, users accessed the FridgeCam on desktop devices in order to ensure it was still working, to show the program to others or else as a memory aid prior to going shopping. Although the device was not used as expected, it assisted in demonstrating the reality of everyday integrated practices and where values within food management, consumption and disposal were acted upon.

Designing beyond habit: opening space for improved recycling and food waste behaviors through processes of persuasion, social influence and aversive affect

In another novel study, Comber & Thieme (2013) investigated the effects of a garbage bin camera designed to promote conscious reflection on waste disposal intentions and behaviours through social influence and aversive effect. In this context, waste was viewed as a habitual behaviour that can be interrupted and over time, altered.

The BinCam is a two-part system where a mobile phone is attached to the lid of a kitchen garbage can. When the lid is closed, the device’s accelerometer is triggered and takes pictures of the waste. These photos are then uploaded to a Facebook page and can be immediately viewed by all BinCam members. This Facebook platform was designed to leverage participant engagement and social influence. The second part of the technology enabled the tagging of the number of both recyclable items and the number of food items. Using this, improvements in waste behaviours were also tracked and visual feedback was provided to each household.

The technology was designed to specifically target individuals between the ages of 18-35 who are typically under-aware of recycling issues. However, in this sample the particpants claimed to already be very aware of recycling issues. Researchers believed this bias resulted in little behaviour change. Rather than actually changing behaviour, the technology enabled increased self-reflection on waste disposal practices.

Fridge Fridge on the Wall: what Can I Cook for Us All? An HMI study for an intelligent fridge

In a study conducted by Bucci et al. (2010) a new Smart Fridge product was researched and developed. Viewed as an intersection between sociology and technology, the goal was to have a technology that seamlessly integrates into everyday life and supports users in their daily tasks.

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“In this scenario the user is at the supermarket but she forgot the shopping list. She requested a real-time updated list to her fridge and received it by an sms on her mobile phone” (Bucci et al. 2010)

Referred to as the ZmartFRI, the smart fridge technology is a coupled display system between a fridge and the user’s mobile device. Meant to become a family information hub, the fridge is able to alert users to product expiration dates, suggest recipes based on foods that are available or about to expire, fill in and send by SMS or email the house’s shopping list and send and post messages for the house residents. The ZmartFri is able to do all of this via a RFID antenna and a reader inside to read each product that has a smart label attached to it. Although the prototype is still virtual, it represents a promising avenue for further research.

It seems technology is well on its way to facilitating improved awareness and conscientiousness of waste disposal practices. Although it is difficult to asses their ability to actually alter food waste practices based on the study design of the presented work, this area presents promising avenues for future research.


  • Bucci, M., Calefato, C., Colombetti, S., Milani, M., & Montanari, R. (2010). Fridge fridge on the wall: what can I cook for us all?, 415.
  • Comber, R., & Thieme, A. (2013). Designing beyond habit: Opening space for improved recycling and food waste behaviors through processes of persuasion, social influence and aversive affect. Personal and Ubiquitous Computing, 17(6), 1197–1210.
  • Ganglbauer, E., Fitzpatrick, G., & Comber, R. (2013). Negotiating food waste. ACM Transactions on Computer-Human Interaction, 20(2), 1–25.

Trash Talk: Post 2 – Elements of Successful Interventions

This post was originally posted on FoodFocusGuelph and is part of a four part series on household food waste.
          Once the drivers of household food waste are better understood (see last week’s blog post for more on this), it is time to consider the design and implementation of interventions. Both practitioners and academics around the world have begun tackling this difficult task. From awareness-raising efforts to the installation of fridge camera technologies, researchers are creatively designing and testing methods to reduce household food waste.
          Before diving into the details of these various interventions, I would like to discuss some behaviour change elements identified in the literature that can contribute to an intervention’s overall success.
Motivations Vary
          First and foremost, it is important to keep in mind that motivations for managing household food waste can vary greatly. Some people are compelled by messages highlighting the economic costs of food waste, while others respond more strongly to messages highlighting the environmental repercussions. These motivators are shaped by several factors from age and income to values and priorities. Thus, when designing interventions it is important to recognize that no one message will work for everyone and that every message should address different motivators.
Convenience is King
          In order to be effective, suggested behaviour change has to be convenient for people to implement. This means providing the structural conditions required to facilitate the target behaviour. One example of this can be found in a study conducted by Bernstad (2014) where two interventions were designed to encourage food waste source separation rates. The first was an informational campaign aimed at increasing participants’ knowledge of source separation. The second intervention was the installation of a food waste container in participants’ homes. The results are perhaps somewhat unsurprising, the informational campaign had no effect on the target behaviour, but providing better equipment significantly increased source separation of food waste. This emphasizes both the importance of convenience as well as the fact that it takes more than information alone to facilitate behaviour change. Which brings us to our next point….
Information Alone is not Enough
          In a systematic review of consumer food waste reduction and prevention interventions, Stöckli, Niklaus, & Dorn (2018) concluded that informational interventions alone are ineffective at changing consumer behaviour. Given the practices that cause food waste are deeply intertwined in the routines and habits of everyday life, they are not easily influenced by only providing best-practice information.
          However, informational campaigns can be successful when they address a specific behaviour not yet being performed, or else when paired with other intervention types. For example, strategies that are designed to support related prevention practices, rather than only the waste itself, can be more successful at fostering behaviour change. Additionally, for information campaigns to be more successful, Stöckli, Niklaus, & Dorn (2018) suggest the target behaviour must be strongly supported by related social norms. This is a challenge in the case of food waste as social norms can be at odds. Although research suggests that many feel guilty about food waste, there also exists a general normalization of waste in North America. Until all related social norms shift towards viewing food waste as being unacceptable, informational campaigns on their own may have limited success.
Reality Check
          The literature on food waste suggests that people are not aware of how much food they actually waste. Therefore, it is important to gently confront people with the reality of their food practices. Certainly, we all aspire to do better and social-desirability bias can lead us to exaggerate desired behaviour. However, facing the reality of our behaviour is an important first step to change. Along these lines, interventions should seek to address any denial of responsibility for the food waste problem.
Avoid Shame and Blame
          That being said, food waste in an emotionally-complex issue. Thus, it is important to provide feedback to participants without the use of shame and blame. Given food waste is often the result of competing values, interventions should shift away from messages with a moralistic stance that induce guilt. We must respect that no one actually intends to waste food. Rather, it is often the result of various behaviours and moments of consumption occurring before food actually becomes waste.
Behaviour Change is Complex
          In some ways, the stars must align to facilitate behaviour change of any kind. There are many elements to consider – skills, knowledge, facilitating conditions, attitude shifts, etc. In order to better understand this process, the Theory of Planned Behaviour is often used to explain food waste behaviour. This model identifies a gap between intention and action. This suggests that although people intend to reduce their food waste, their actions do not always follow suit. Based on this concept, interventions targeting only intention to reduce food waste will have a limited effect on behaviour. However, interventions that provide support for this intention-behaviour gap will have an increased likelihood of success.
          Bridging this gap can be difficult and to some extent, interventions must encourage change, without actually changing much. Along these lines, Hebrok and Boks (2017) have suggested the following;
“A successful design intervention will contribute to nudge people to reduce their food waste, perhaps without them having to change their attitude, be educated or raise their effort greatly.”
Intervention Types
          Current interventions have been building off some of these concepts. As a result, there are four primary categories of interventions designed to reduce consumer food waste;
  1. Technology that helps people plan their food purchases and consumption while keeping an overview of food they have at home.
  2. Packaging and storing solutions that extend product shelf-life.
  3. Information and awareness campaigns.
  4. Systemic change to the food system through the development and implementation of policy.
Stay tuned for next week’s blog post where I’ll discuss some specific interventions in more detail!