JOURNAL HIGHLIGHTS BY Steve Ranger
More than a third of fruit and vegetables, equivalent to 2.4 Mt of produce, is lost or wasted between production and sale in the UK, with just four crops - apples, onions, carrots and potatoes – accounting for much of that waste. And it could get worse yet.
Quality requirements and supply and demand mismatches are a big part of the problem, along with a failure to manage the quality of the produce after it has been harvested, according to researchers at Cranfield University.
‘Through climate change effects, reduced pesticide availability, changing consumer behaviour and increased pressure to reduce resource/energy inputs during pre- and postharvest handling, food loss and waste risk is likely to increase in the short term unless targeted, coordinated action is taken to actively promote its mitigation,’ they warned.
Food loss and waste (FLW) accounts for 15% of total carbon dioxide equivalent emissions from the food supply chain – with fruit and vegetables among the largest contributors.
These are highly perishable because they remain biologically active after harvest, which means they have to be stored carefully. This can be a problem as the pre- and postharvest behaviour of fresh produce and its impact on wastage are often poorly understood.
‘Knowledge gaps in understanding the biological drivers of FLW in the supply chain currently hinder effective mitigation strategies,’ notes the paper published in SCI’s Journal of the Science of Food and Agriculture, which also points out that data about the loss and waste risk in fresh produce is inadequate, especially for low volume crops like raspberries.
The researchers carried out a systematic literature review to identify the current estimates of food loss and waste for potato, apple, pear, carrot, onion, cabbage, broccoli/cauliflower, tomato, sweet pepper, cucumber, lettuce, strawberry and raspberry crops - the majority of UK fruit and vegetable market by value and volume, while excluding import-only products. They combined this with a survey based on interviews with managers and directors in the food industry supply chain.
The researchers calculated the total loss and waste of UK horticultural products stands at around 2,395 kilotonnes/year, or 37% of the total supply. The researchers said a total of 71% was contributed by four crops: apple, onion, carrot and potato. The greatest proportion of loss and waste occurred during primary production – this accounted for 1486 kT or 58% of the total.
‘This was predominately a result of the imposition of quality standards during harvest, supply/demand mismatch or the influence of pre-harvest risks,’ the researchers said.
The paper said that quality standards are a leading driver of loss and waste, with produce rejected because of a perceived lack of marketable quality at harvest or after its quality has declined in the supply chain.
These quality requirements are unlikely to be relaxed. ‘Survey results indicated that historic trends in increasing specification strictness were likely to continue as a result of retailers seeking differentiation in a saturated market environment or by growers in competition with cheaper imports,’ the paper said.
In any case, the paper also suggested that lowering quality standards is unlikely to lead to a meaningful reduction in loss or waste: survey respondents mentioned an increase in customer complaints when quality rules were relaxed due to shortages.
Other factors contributing to wastage include variations in weather that impact on both yield and quality; the research noted that field vegetables were most likely to suffer from this, and that increasing unpredictable seasonal weather patterns with climate change are likely to increase the risk. Protecting crops is one option here; for example, using polytunnels reduced strawberry losses from 30% to 8–12%, but such efforts may not be feasible for lower value crops.
‘Field vegetables are exposed to the greatest environmental variation, have lower value, and limited control on environmental conditions... Biological solutions, such as crop breeding, may have minimal economic impact at the same time as reducing FLW through increasing resistance to abiotic stress (eg drought), P&D activity or crop uniformity,’ the researchers said.
Ewan Gage, Research Fellow in Food Systems in the School of Water, Energy and Environment at Cranfield University, told C&I that changes in expectations of quality standards ‘would be of massive benefit’ in terms of reducing waste. This would need to come from both supermarkets, and from consumers. Supermarkets are often responsible for setting overly strict specifications – using quality to differentiate from their competition. Also, the low prices paid by consumers for fruit and veg are likely to further increase waste risk as there is little economic incentive to reduce losses.
Gage said it is more likely that FLW will increase rather than decline. ‘At farm level, the ability of growers to get produce into current quality specifications will be increasingly impaired by loss of pesticides and the effects of climate change as both of these worsen with time. Other challenges – particularly ongoing problems accessing labour, energy costs and downward price pressure – will also continue to impair the ability to grow crops to target quality/make lower quality produce economically viable,’ he said. Unless customers and supermarkets can become more accommodating of more variable quality in produce waste will remain a problem, he said.
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