In Switzerland, 300 kilograms (661 pounds) of food ends up in the trash bin per person, every year. But we’re talking about the “food basket,” and that includes a variety of items, like yogurt, leftover green beans, to two-day-old bread.
But going through the virtual food basket, scientists at the research institute Agroscope and ETH Zurich were able to identify one food item that is thrown out more often than any other item, and surprisingly, it is the lowly potato.
Potatoes were first domesticated in southern Peru and the extreme northwest of Bolivia between 8000 and 5000 BC. Since that time, over 5,000 varieties of potato have been developed, making them a staple crop and comfort food in many countries around the world.
So it is strange that the potato would be the one food staple that is tossed in the garbage bin more than other food products. Researchers wanted to find out what was behind this phenomenon, and as doctoral student Christian Willersinn, who worked with the group of researchers led by Professor Michael Siegrist said, the “aim of the study was to deepen the discussion of food waste by looking at a single product.”
From field to fork
The researchers found a study with precise figures on potato waste in England, but studies elsewhere in the world were lacking. So in the Swiss study, researchers examined potato waste from the field to the fork. This means they looked at potatoes, starting with the producer and going up the line to include the wholesaler, retailer, processor and finally, the consumer level.
The researchers also looked at the quantities of “table” potatoes and processing potatoes (such as those processed into chips and crisps). They also looked at organic and non-organically produced potatoes in both categories. To correlate data for the study, the team looked at data from 220,000 quality assessments at the producer stage, along with surveys of wholesalers and retailers.
They then surveyed 2,000 families to ascertain potato waste by household. And as an additional part of the survey of families, 87 people kept a diary for 30 days to track their potato consumption along with data pertaining to how many potatoes were purchased and how many were thrown out, and why.
Results of the survey and study
The first thing the team learned was that the Swiss waste a lot of potatoes. As much as 53 percent of conventionally raised potatoes are thrown away. With organically grown potatoes, the waste rises to 55 percent. According to the study, “for processing potatoes (those used for making chips and crisps), the figures are lower: 41 percent of organic potatoes are discarded, compared to 46 percent of those from conventional production.”
The researchers found that the higher percentage of waste in conventionally produced processing potatoes is due to over-production, something rarely seen in organic farming. However, organic table potatoes see more waste because they don’t always stand up to the quality of conventionally produced potatoes.
But losses are seen at all stages. A quarter of potatoes are lost at the production stage, while a further 2 to 24 percent are rejected by wholesalers while being sorted. Only one to three percent are discarded by retailers, and a further 15 percent are wasted by consumers. So we’re looking at almost two-thirds of a potato crop being lost to waste. That is a lot of potatoes.
Blame the waste on the consumer
The figures tell the true story, consumers want perfection and high quality in their food products. If a potato, or for that matter an apple or pear has a little blemish on it, we choose another item. If we peel a potato and find a part of it blemished, we may throw it out rather than cut out the bad part.
Consumer health protection, regardless of governmental health authorities in the U.S., the UK or Canada, also leads to waste. This is why producers reject one in three potatoes at the production level. The research team says it is up to consumers to reconsider their preferences as well as their buying and eating habits.
This study was carried out as part of the National Research Programme NRP69, “Healthy Nutrition and Sustainable Food Production”, funded by the Swiss National Science Foundation (SNSF).
This most interesting study, “Quantity and quality of food losses along the Swiss potato supply chain: Stepwise investigation and the influence of quality standards on losses,” was published in the journal Waste Management (2015) September issue.
