Ancient Food Safety: A Story of Ice and Fire

Food is delicious and nutritious, but one bad meal could kill you. Throughout the ages, new technology has helped us enjoy our food without getting sick.

Food is our fuel, but it can also be fatal. Whether you’re accidentally eating parasites hiding inside pork or fish, catching bacterial infections from eating eggs or avoiding beef because you’re worried about mad cow disease, there are loads of things hiding inside our food that can make us sick. Avoiding meat won’t keep you safe either—almost half of all food poisoning cases are caused by fruits, nuts and vegetables that are past their prime.¹ Then, on top of that, there are all the diseases that can be transmitted by eating any food that’s been contaminated with bugs like E-coli– still the biggest cause of travellers’ diarrhoea across the world. ²

Illness has always been a spectre lurking behind every meal–simply putting food in your mouth is an inherently dangerous thing to do. Luckily, we humans are an ingenious bunch, and long before Homo sapiens were on the scene, our ancestors were creating new technologies and methods to help us eat without getting ill.

Killing bacteria: No dragons required

The first major jump forward in food safety came almost 2 million years ago, on the back of one of mankind’s greatest early discoveries: fire. Cooking food kills all kinds of bacteria, parasites and fungi that might be lurking inside it because at high temperatures (above 60°C) proteins start to break down. This means that the machinery inside these microbes eventually stops working and they die, rendering them harmless.³ Once prehistoric humans discovered fire, it wasn’t too long before they started cooking their food, improving its nutritional value and making it far less likely that the dinner they just killed would end up killing them in return.

Freezing Food: “Winter is coming”

The advent of cooking was a huge leap forward, but we were still living largely hand-to-mouth. As populations grew in size, we needed ways of storing food to keep it safe to eat after long periods of time, and make sure there was enough to last through winter and famines. Luckily, we didn’t just invent one way of keeping our food fresh–we invented loads.

One of the first food preservation techniques humans developed also relied on modifying temperature: freezing. The first ‘freezers’ were just holes in the ice in which arctic communities used to bury their spare food, but they worked on the same principle as modern freezers:  drastically reducing the temperature to stall the growth of bacteria and fungi, therefore keeping food fresh for longer.

All Bugs Must Die: “Valar Morghulis”

Until relatively recently, most humans simply didn’t have access to sub-zero temperatures to store their food in. Luckily, they found multiple other ways to keep their food fresh: drying it out by leaving it in the sun or burying it in salt, pickling it in vinegar, fermenting it into alcohol or even adding sugar to make jam. We didn’t know it at the time, but all of these methods work on the same principle as freezing: by creating an environment that is inhospitable for microbes to grow in.

Ancient food preservation methods

Drying and salting remove moisture from food, starving bacteria of water; pickling makes the environment too acidic for bacteria to grow well; alcohol literally dissolves bacteria into bits; and very high concentrations of sugar suck all the water out of bacteria, leaving them shrivelled and helpless.

These natural preservation methods kept humans fed for hundreds of years, but after the discovery of microbes and the acceptance of ‘germ theory’ (the idea that illnesses are caused by tiny living things),⁴ we started to study and understand bacteria and develop new, synthetic preservatives. Nowadays, chemical preservatives like sodium benzoate and sulphur dioxide are often added to processed foods, as they allow manufacturers to keep food fresh without adding natural preservatives like sugar and salt which affect its taste.

Modern preservatives and storage techniques are really effective at preventing food from going off quickly, but they are no defence against infections that have hidden inside our food from the very beginning.

Read more to see how we’ve developed new approaches to keep ourselves safe.