Is growing food wasting water? This was the leading question displayed on gigantic billboards Waitrose’s Amy Lance passed while she was driving through California’s agricultural heartland recently
I was travelling through the Central Valley from my base at Apricot Lane Farms just outside Los Angeles, northwards to the University of California, Davis (UC Davis) in the middle of the Sacramento Valley. It was a long, hot trip although I always find driving in the US quite enjoyable; large roads, large cars (my mistakenly upgraded rental was a massive, automatic door, mini-van instead of a car, so I really should have looked into joining up with Uber for the day!), large service stations that look like you’ve entered the Wild West and a good bit of country music on the radio.
California produces over a third of the US’s vegetables and over two thirds of the country’s fruit and nuts, so the scale is impressive but the future sustainability of farming here is a growing concern as the billboards suggest.
Post-harvest lessons
Posing the question “Is growing food wasting water?” really emphasised the reasons why I was driving up to UC Davis in the first place. I had enrolled on the annual UC Davis post-harvest technology short course for the next two weeks; one week classroom and lab-based and one week in the field visiting an assortment of Californian fresh produce growers.
I believe that learning more about post-harvest technology can help farmers, suppliers, seed breeders, retailers, technology providers, and many others worldwide to reduce waste in the supply chain from seed, all the way through to the consumer’s fridge. Reducing food waste has become a goal in itself – the global target is for us all to cut food waste in half by 2030. However it is also a way of ensuring we do not lose what we have already produced, of boosting food security, improving livelihoods, reducing greenhouse gas emissions, creating increased land use efficiency and ultimately saving water. I believe we are now in the age of food efficiency.
So, I hope you can see why I thought that being more educated in post-harvest technology is critically important. Around 60 others from 25 countries across six continents have also enrolled on the course – from Taiwan to Uzbekistan, New Zealand to South Korea – and will learn with me how to reduce post-harvest losses whilst improving the safety, quality and marketability of fresh horticultural products.
Fresh produce is easily damaged, it has a high water content, it is extremely diverse in terms of genetics, tissue type, physiological state and is ultimately still alive post harvest. The challenge begins here, to keep it fresh, beautiful and nutritious. It’s even more difficult when we are seeing an aspirational shift from maximised production and storage life to maximised quality, flavour and texture.
Aha moments
I don’t want to plough on about post-harvest technology and fruit physiology, but I do want to mention some of the aha moments I have had as well as some interesting technologies that could have a really positive impact over the next few years.
Could we be smarter and identify what gasses are given off when a defect occurs? Can we stop freeze damaged fruit such as citrus going out of the door by testing the fruit with a breathalyser to identify if ethanol is omitted?
Could all of our packhouses be light-free and pitch-black in the future? Shining high energy light on some products can excite specific molecules, and as they come back to their original state, they release colour. Using this florescence, which has already been tried on citrus, could determine defects such as freeze damage, thrip damage and decay.
Along with the understanding that plant health under the soil surface is the root cause of any post harvest disorders, could carefully treated, well-managed compost tea actually be a biological control for fruit post-harvest decay rather than the focus of a growing safety concern?
Product freezing temperature has surprised me, now knowing that cherries freeze at -2.1°C, cauliflower at -0.8°C, pears at -1.7°C and asparagus at -0.6°C, could we all be working at much lower temperatures? Will we see more scenes such as Ice Bar London?
Gene technology
Aside from new uses and innovation stemming from the technology that has been in the market place for a few years, Arctic apples and CRISPR mushrooms are just about to enter the US marketplace bypassing regulation and revolutionising post-harvest technology.
Arctic is produced through RNA interference, suppressing the polyphenol oxidase (PPO) in an apple to prevent browning. CRISPR mushrooms have been developed through a gene-editing tool CRISPR–Cas9. It again knocks out one of six PPO genes—reducing the enzyme’s activity, which causes browning, by 30%. Neither method is introducing new or foreign DNA into the product or genetic material from plant pests such as viruses or bacteria. Both have recently surpassed US regulatory process and have received a green light from the US government to be marketed.
This unique process can easily modify plant DNA without changing the plant itself—except to make it tastier, more nutritious, quicker to market, easier to ship, machine-pickable, lower demand of water and have the ability to flourish in a heat wave. This technology is seen as fine tuning the products own genetic traits or speeding up a process that can naturally occur, evolving quicker to today’s demands.
Will we fall behind if this fast, efficient solution to many post-harvest and pre-harvest problems is not seen in the UK in the future? And should products developed using this technology be considered genetically modified organisms or not?
