When consumers see fresh produce on the market shelf or on their plate, they often have very little idea of the losses incurred on the journey from the farm.
Understandably, a consumer may feel upset when a fruit or vegetable spoils soon after purchase, or may not even buy fresh produce with imperfections. But losses at the point of sale dwarf losses that occur during the months that go by after harvesting, during which packing, storage and transport activities occur.
Losses are however often preventable or manageable if best practices are followed. Part of the mission of food safety researchers at the Department of Plant and Soil Sciences at the University of Pretoria, led by Professor Lise Korsten, is to provide farmers, consumers and everyone in between with information to minimise waste and losses.
To determine where and how severe food losses are, researchers consider all the links along the supply chain, starting from when the farmer plants a crop to when a consumer plants a fork into the food product. The first step is to ensure that seeds and seedlings are of a good quality and not diseased.
“We test seeds for viability in South Africa because they must reach at least 80% germination,” says Korsten. “The farmer needs information that can help them cultivate properly, and knowledge about plant material and the environment is therefore important to prevent losses.”
Major losses can happen during production due to pests and diseases, which is why it is so important to protect crops during production. Losses can also occur up to and at the point of sale. Unfortunately, at this stage spoilage of fresh fruits and vegetables often means they are not fit for human consumption - thus unsafe to eat. Fresh produce that has imperfections such as bruises, which might indicate spoilage, is sometimes sold to the informal markets, and ultimately to unsuspecting consumers.
“The longer the supply chain is, the more you lose and the harder it is to maintain quality and safety,” she says.
One way UP researchers have helped prevent losses is through the introduction of essential oil sachets that can be put in boxes to reduce avocado diseases. The product relies on cutting-edge, but affordable, nano-technology, edible oils and essential oils to help manage post-harvest losses of these fleshy fruits. This research was completed by PhD student Dr Malick Bill in collaboration with Prof Dharini Sivakumar from the Tshwane University of Technology.
Prof Korsten emphasises that the responsibility of food safety falls on everyone at every link of the supply chain, including farmers, researchers and inspectors. What connects all these links is a cycle of knowledge generation and implementation.
She adds that losses, wastage and food safety go hand in hand, and that consumers should be informed. Ensuring food safety can be as simple as looking at food to determine whether it is spoilt, but human pathogens and contaminants can hide in plain sight. This means that practices like washing, cooking and existing indigenous knowledge systems related to the preparation and preservation of food are important to secure safe food for all.
The fresh produce safety research group at University of Pretoria works on all aspects of safety from the farm to the table. Prof Lise Korsten is pictured front and centre.