It is a modern culinary conundrum – we want food to be wholesome and fresh, but we also want bread that doesn't go stale after two days.
While many of us love to hate processed food, it isn't all bad, says science writer Nicola Temple.
It's time we took a more realistic view, says Temple, the author of Best Before: The Evolution and Future of Processed Food.
“When I began this book I thought it would be another exposé of the food industry filled with horrifying stories of how our food is manipulated. But as I got into it, my views started to shift slightly.”
The ability to process food has given humans a huge evolutionary advantage, she says.
From pounding potato-like tubers with rock to make them more digestible to eventually harnessing fire to cook and smoke meat, we've been able to gradually access more and more calories with less effort.
“So we didn’t have to develop these great big jaw bones and teeth. Our small faces and small teeth enabled those resources to be directed elsewhere – building bigger brains, for example.”
This, in turn, allowed us to develop complex languages and civilisations, Temple says.
Later forms of food processing – such as cheese-making and culturing yoghurt – allowed humans to access calories from dairy which would have unavailable to us otherwise, she says.
“There is evidence cultures have been collecting milk for about 9,000 years. There’s also genetic evidence that people at that time were mainly lactose-intolerant.
“So why would you be collecting milk if you couldn’t actually drink it?”
The theory is it was probably being processed into cheese or fermented into yoghurt which reduces the lactose content, she says.
That has had a profound impact on humans.
“About 35 percent of the world can now digest milk, so it changed our DNA.”
More recently, food processing has brought huge benefits to human health.
Before French chef Nicolas Appert developed food canning in the 19th century, soldiers and seamen were just as likely to die from malnutrition as in battle.
But our modern world of unbridled convenience brings both benefits and risks, she says.
One concern about processed foods is the ingredients added to enhance flavour, preserve colour and extend shelf life.
Temple is uncomfortable when food processing involves deceit.
“The fact that a very mature cheese has a particular sharpness and flavour to it then you sort of know it’s been matured for a certain length of time.”
But that flavour can be replicated by adding things such as amino acid and enzymes to cheese.
Likewise, the sourness of sourdough bread’s can be ‘faked’.
Bagged salads are convenient but also problematic, she says.
“Each one of those little stalks has been cut and so it’s a wound, if you will. With each of those wounds, all of this biological reaction happens and enzymes start to destroy it.
“A whole head of lettuce has one cut. These bagged lettuces have thousands of cuts and to compensate you need to do a lot more to keep them fresh for longer.”
Also, a lot more food is wasted when it's pre-bagged, she says.
Sugar has become a functional food and, as it has dropped in price, integral to food processing.
“It can be used to preserve, it can be used to counter the flavour of other additives.”
And consumers have developed a high tolerance to it.
“If one manufacturer of pasta sauce ups their sugar content it tends to fly off the shelves quicker, so other manufacturers up their sugar content a little bit to match and you get this bit of a sugar war going on and our overall threshold for sweetness levels increases as a result.”
Just as some preconceptions about processed food are misplaced, frozen food is unfairly maligned, she says.
“Frozen product is flash-frozen much closer to the site where it’s been picked, whereas so-called fresh fruit may have been in transport for a week, ten days or as much as two weeks.
“We have a real stigma around frozen food and it’s time to rethink that.”
Temple's main concern for the future of food is not so much the processed stuff itself, but our reliance on convenience.
While her grandmother made most of her own clothes, Temple says she can barely sew – a practical skill lost in two generations.
“If we are continually depending on others to make our food, is that a skill that within a very short period of time we will also lose?”