Supply chain waste

Waste happens in multiple ways along the supply chain and for multiple reasons.

Farm products

Field losses in Canada were estimated by Gooch et al. (2010) to be nine percent of total waste, revised upward to 24% in Gooch et al. (2019). As discussed earlier, nutritious and safe food does not necessarily leave the farm, for a number of reasons including: cosmetic requirements[1] that do not make it worth harvesting; harvesting inefficiencies (human or machine); plant parts deemed inedible even though they can be eater (see Goal 9);  low prices; and losses during on-farm primary processing and storage. Given levels of field waste, significant amounts of food degrade on the field surface in ways that are sub-optimal for nutrient uptake by subsequent crops. Food that is harvested and then rejected is often left in cull piles and not composted or fed to animals.  Farmers often do not have room in their packing house for lower grade products. An Ontario produce farmer, speaking prior to Ontario’s changes to the produce grading system, argued that, “even though the Canada No. 2 grade could be sent to processors or manufacturers, we don’t usually bring them out of the field.” Processing prices are typically substantially below fresh market prices and farmers usually need an advance contract with processors to make the secondary product supply chain work; that is, they cannot necessarily sell product to processors that was grown for the fresh market but failed to meet the standard. On top of this, the standard boxes used to ship produce can only accommodate a certain size in order to meet quantity descriptions on the box, thereby providing a further incentive to leave food in the field (Schneider, 2008). When a producer does have a contract directly with a retailer, those specifications are usually more exacting than government grading standards. A major Canadian retailer executive stated that, “we don’t accept those [government] standards because they’re minimum standards. What we do is create our own quality standards, which we call quality specification.” For instance, this retailer has about 850 quality specifications for their fruits and vegetables alone (personal communication, senior food retail executive, February 17, 2011).  For all these reasons, some 30% of produce may never leave the farm field due to cosmetic deficiencies and how marketers perceive consumer reactions to them (Hingston and Noseworthy, 2020).  These limitations can be compounded by some production insurance programs that do not allow unharvested crops to be donated (see Goal 6).

Processing and packaging

Nutritious food is lost during processing for several reasons. It may be deemed unsuitable, the food may be substantially trimmed to suit the process or cultural perceptions of quality processed goods, the batch can be lost due to human and equipment errors or breakdowns, motion inefficiencies can damage the batch, too much was purchased for demand, or pre- and post- processing storage was ineffective. Gooch et al. (2010) estimated packaging / processing waste at 18% of total food waste,  and Gooch et al. (2019) revised their estimate for primary, secondary and tertiary processing (what they call processing and manufacturing) to 47%. They conservatively concluded that about 40% of that was avoidable. The Québec Ministry of Agriculture, Fisheries and Food estimated that between one-fifth and half of the industry’s food waste was fit for consumption in 2012 (Fortin, 2014).

Non-perishable food processing and packaging errors occur during the manufacturing process. A small percentage of this product ends up in the charitable food system (Gooch et al., 2019), so some of it is consumed. However, food banks are sometimes subsequently forced to dispose of the donated goods, but how much waste this generates is difficult to determine. There is some evidence that the charitable system makes it more feasible for manufacturers to donate (and often receive tax donation credits) than to repackage the goods (Midgely, 2013).

There is also both a positive and negative relationship between packaging materials and styles and food waste.  This is discussed under Goal 5, Food Packaging Changes.

Distribution and Shipping

The sometimes convoluted movement of food within a region likely increases the gap between harvest and store purchase. Losses during the shipment of fresh goods from farm to retail, especially with refrigerated, long distance hauls, can result in load rejections at retail or culled pallets. An interview with a senior executive at a major Canadian retailer revealed that in the late 2000s the company was rejecting 75 truckloads of produce per week at the distribution centres (DCs) across Canada that amounted to about 2,722 tonnes a week or 141,570 tonnes a year. This did not include what the retail stores rejected from the DCs. McCallum et al. (2014) provided details on the supply chain challenges facing major retailers as it relates to wasted produce. The buyer protocols can also create waste in the meat sector. Waste along the chain due to inconsistency in carcass composition and production adds an estimated 10% to the end price as meat not meeting specifications is rejected somewhere along the chain (Gooch et al., 2010). Augmenting this problem are shifts in consumer preferences for tougher cuts and organ meats, and reductions in organic meat quality associated with industrial production (see Goal 9). Gooch et al. (2010) estimate distribution losses at three percent of total food waste in Canada, revised downward in Gooch et al. (2019) to 2%.


Problems with cooling infrastructure along the supply chain (from farm to home fridge) leads to waste. The perishable food system runs on cooling and freezing and a significant percentage of the cooling units have been old (Garnett, 2006). The opportunities for failures, resulting in lost food, are significant. As well, not all horticultural producers can afford sophisticated field chilling equipment. Pre-cooling acts to remove the heat stored in produce from the field. This affects particularly local growers who do not usually have the resources to field chill their produce prior to shipping. Product immediately loses shelf life, and without being able to move local food quickly, retailers risk serious losses.


Buyers often misforecast requirements (Karolefski, 2015) and then reduce orders when conditions suddenly change, leaving the suppliers without a sale (McCallum et al., 2014). This occurs because retail buyers typically have more economic clout than suppliers and contracts shift economic risks to the weaker actors in the supply chain. Alternately, retailers may be afraid of shorting so they over-order. The amount of available food per person in retail stores has increased during the last decades (Gustavsson et al., 2011). The appearance of abundance is believed to be attractive to consumers, thus increasing sales in the long-term, even if it generates waste in the short-term (Gunders, 2012). Constant stock rotation, however, promotes waste as discerning consumers favour newly stocked produce over those that are close to expiry (Gustavvson et al., 2011). Overstocking can also lead to over-handling by both staff and customers, which may damage items and add to waste generation (Gunders, 2012). Alternately, buyers may focus on “deals” from international suppliers, and purchase at volumes to make the deal happen, even if it doesn’t line up with demand (Mena et al., 2011).

From retail document analysis and interviews conducted by our team, we estimated total in-store shrink (including waste and theft) by Canadian retailers (Table 2)[2].

Table 2: Estimated shrink levels for different product categories in supermarkets (adapted from Kohn, 2011)


Department Shrink levels (%)
Produce 8 to 11
Bakery 10 to 12
Grocery 0.5
Meat 3 to 4
Deli 6
Meal solutions 8

On average, a typical supermarket’s targeted shrink is six and one-half to seven percent of everything that gets purchased for sale. Reducing shrink from nine to seven percent would represent a significant reduction and make a huge difference to the bottom-line. To limit shrink, a store must counteract prominent driving forces for freshness and quality at a low price.  Gooch et al. (2019) estimate direct retail losses at 4% of the total food waste in Canada, but their practices have both up and downstream impacts on food waste, so their indirect total is much higher.

Food Service

Gooch et al. (2010) estimated that restaurant/food service waste represents eight percent of total Canadian food system waste, revised slightly upward to 9% by Gooch et al. (2019). In U.S. restaurants, diners wasted nine percent of the meals they bought, partly because of increased serving sizes (Lipinski, Hanson, Waite, Lomax, Kitinoja, & Searchinger, 2013). Since the 1970s, there have been significant increases in portion sizes in the U.S. (Nielsen & Popkin, 2003). For example, the Centers for Disease Control (CDC) documented two and one-half to four fold increases in serving size for certain popular fast food items between the 1950s and the present day (CDC, n.d.), the average pizza slice has increased by 70% in calories and the average muffin has more than doubled in calories. Portion sizes served in restaurants and other food service establishments can range from two to eight times larger than the USDA’s recommended standard serving sizes (Regional Municipality of York, 2013). This appears to have carried over into Canada as well, though data are less available.

WRAP U.K. found in a survey of a range of food service operations that 21% of food service waste is from spoilage, 45% is from food preparation and 34% from plate waste. Different types of restaurants show different profiles, for example, there is lower plate waste in fine dining establishments and higher waste from kitchen prep, while restaurants without sit-down have contrasting ratios (Williams, Leach, Christensen, Armstrong, Perrin, Hawkins et al., 2011). In many restaurants, a lack of trained chefs and fixed menus can limit capacity to adapt to excess inventory, whereas restaurants with skilled chefs and weekly menu changes are less likely to waste food. In fact, the reduced waste is part of how some keep prices affordable (Rosenblatt, 2009). The FAO report (Gustavvson et al. 2011) noted that certain kinds of procurement practices mean that more food preparation happens off-site so the waste is generated elsewhere in the supply chain (in North America, suppliers to food service such as Sysco). A detailed analysis of profit-making hospitality operations found that, “two-thirds of the food that was thrown away could have been eaten if it had been better portioned, managed, stored and/or prepared, with the remaining one-third consisting of items that are ‘unavoidable waste’ as they are not usually consumed (e.g. banana skins, vegetable peelings)” (Williams et al., 2011, p. 4).


Food waste in the home includes uneaten food in the refrigerator, plate waste and liquids poured down the drain. Gooch et al (2010) estimated that 51% of waste is generated in the home, revised to 47% in their follow up work because of the addition of higher waste estimates in earlier stages of the supply chain (Gooch & Felfel, 2014). But Gooch et al. (2019) have dramatically lowered consumer contributions to total waste, to 14% of the total. In their study of U.K. food waste, Quested and Johnson (2009) concluded that 64% was avoidable edible waste, over half of which was not consumed in time and 41% was a result of over-serving. Another 18% was potentially avoidable, depending on family consumption patterns (e.g., broccoli stalks, apple and potato skins, leafy greens of root crops like beets, chewier parts of meat) and only 18% was inedible, requiring consumption by other organisms or composting. Parizeau et al. (2021) also found 64% was avoidable edible waste in household composition audits in Guelph, ON. Gooch et al. (2019) have only estimated avoidable household waste at 46%. Following a 2014 audit, Metro Vancouver concluded that over 50% of the food being wasted was avoidable (Metro Vancouver, n.d.).  Regardless of the estimate, avoidable waste is a very large percentage of the total. An Oakville Ontario audit and survey found that food waste increased with household size, particularly younger children due to finicky eating and fears about food safety. The most significant amount of food waste was in fruits and vegetables but most of that was unavoidable.  Grains was the category with the most significant avoidable food waste. Across all categories, 58% of waste was deemed inedible (unavoidable). Dinner produced the most waste. Households in the second lowest income quintile (medium low) appeared to waste more than other quintiles because they were more prone to take advantage of retail promotions and buy in bulk (Gooch et al., 2022).  Lowest quintile households did not have the means to do so.

However, as discussed earlier, structural dimensions across the supply chain contribute to food waste in the home, particularly phenomena such as the weekly stock-up trip (often associated with poor urban planning that positions large stores at some distance from neighbourhoods), store promotions that encourage overbuying, the failure to carry small unit sizes, confusing date labeling, store designs that encourage impulse buying (Ontario Public Interest Research Group, 1990) and consumer deskilling (Jaffe & Gertler, 2006). Certainly consumer behaviours contribute to the situation (Parfitt et al., 2010), but resolving them is not just a question of consumer education as many propose.

COVID-19 disruptions

The lockdowns caused extensive supply chain disruption and accelerated levels of sometimes shortages, sometimes waste.  Because the food system for perishable foods generally runs on a just-in-time inventory approach, if consumer purchasing patterns and transport logistics deviate from the norm, more waste can be generated, with orders unfilled and product shorting   Retail food sales were reported to have increased by 37% within a few weeks of lockdown, historic levels of increase (Dekay, 2020) with associated dramatic declines in food service sales of up to 70%. Many problems resulted from the loss of food service markets and the need to rapidly pivot to produce for retail, a consequence of the very specialist farm production and processing  and packaging systems that target these different markets. Manufacturers found it was cheaper to throw out product originally packaged for food service than repackage for retail needs. Although restaurant waste was reduced for inactivity, many perishables were still wasted with the lost restaurant markets. Milk had to be dumped, mushrooms destroyed, greenhouse production composted, flowers destroyed,  fish from aquaculture operations destroyed and seeding plans were rapidly reconfigured. Farm prices were depressed.  Producers dependent on air transport saw supply guts and transport price increases associated with reduced flights and additional logistics complications (Pratt, 2020).

Labour shortages in meat processing caused backups in slaughter and butchering.  Farmers had to hold back animals on the farm and feed them maintenance diets in an effort to keep the animals from getting too large, but inevitably this resulted in over-feeding and metabolic inefficiencies.  Fruit and vegetable harvest has also been compromised by the shortage of farm labour associated with border and quarantine restrictions for temporary foreign workers (see Goal 8 Labour Force Development), resulting in significant amounts of food unharvested.

Supplies of some non-food products that are essential in food supply chains were also disrupted.  For example, carbon dioxide plays an essential role in meat slaughtering, food and beverage processing and packing and refrigeration.  Compressed CO2 is produced as a by-product of ethanol, fertilizer and hydrogen manufacturing and refining.  Two-thirds of the US facilities producing CO2 were closed at various stages because of labour shortages (White, 2020).

Some potential waste may have been mitigated by a Surplus Food Purchase program of $50 million announced by the federal government in May 2020 and augmented late in the year.

Panic buying and fears of COVID contamination may also have resulted in higher levels of waste in the home.  In at least one study, consumers self-reported increased waste in the 13.5% range, but it could be a lower percentage of food purchased, effectively then an artefact of eating more at home (Agri-Food Analytics Lab, 2020).  Other reports suggest fears about shortages and food insecurity caused households to be vigilant about avoiding waste (Glaros et al., 2021).

These realities are a product of a system that does not attempt to minimize food waste.


[1] Note that some provinces, including Ontario, have largely eliminated vegetable and fruit grading standards.

[2] Note that in our studies, retailers were very reluctant to provide precise figures on shrink, so we were forced to estimate from secondary sources.