Waste not, want not

That funny smell emerging from your fridge because there’s something tucked away there that’s been forgotten about for far, far too long is a familiar scenario for most of us. And all of us must have reached into the ironically-named ‘salad crisper’ only to discover that, far from being crisp, that lettuce we so fancied a few weeks ago has deliquesced into an alarming green porridge.

Taken as a whole, food wastage is a very serious problem. One-third of the food produced in the world for human consumption gets lost or wasted every year, according to the UN’s Food and Agriculture Organization. That’s a staggering 1.3 billion tonnes. To put that in context, every year, consumers in the world’s richest countries waste almost as much food (222 million tonnes) as the entire net food production of sub-Saharan Africa (230 million tonnes).

The challenge

This month’s Coffee Time Challenge is to avoid waste by finding a means of letting you know the condition of the food in your fridge without having to inspect it all. The important thing is that it stops us suffering any nasty surprises when we open the fridge.

It could be visual, it could be chemical, or it could even be olfactory. Just as long as it cuts down on waste.

The idea we have in mind will be revealed in the September issue of Eureka! Until then, see what you can come up with. Submit your ideas by leaving a comment on the Coffee Time Challenge section of the Eureka! website or by emailing the editor: paul.fanning@markallengroup.com

The solution

The Sorex Sensor (a University of Cambridge spin-out) novel sensor technology, gives accurate information about the condition of the food in your fridge. It detects the chemicals released as food ripens or starts to go off – and can give you several days’ warning so that you can consume the food before it spoils.

It could spell the end of throwing away over-ripe fruit and vegetables or mouldy chicken. It could also save you from throwing away perfectly good chicken – as the technology would provide reassurance that it was safe to eat.

The Sorex high-sensitivity mass sensor is based on film bulk acoustic resonator (FBAR) technology. It is extremely small – as thin as a human hair – and can be arranged into arrays on the same chip to measure different targets simultaneously.

Fabricated on a silicon wafer, the sensor comprises a thin film of piezoelectric material that is made to resonate. As chemicals attach themselves to the surface, they change the resonant frequency – which provides an extremely accurate measurement of the amount of a particular chemical on the sensing area.

All you’d need is 3-5 tiny sensor devices, each measuring less than a square millimetre, integrated into your fridge and you’d have an accurate, reliable early-warning system to monitor a whole range of food at the same time – from fruit, vegetables and salad to fish, meat and cheese.

A yellow light would alert you to the fact that a particular food needs to be eaten soon – and a red light would let you know when you’ve missed your chance and the food really does have to be thrown away as it is no longer safe to eat.

The potential savings in terms of food waste amount to billions – not to mention the priceless benefits of helping to save the planet.