A microbiologist has revealed how true the infamous 'five second rule' is and whether dropped food is actually safe to eat. 

Nicholas Aicher, a senior quality control analyst, tested the amount of bacterial growth on food after it had been dropped on the floor and picked up within one second, five seconds, 10 seconds, 20 seconds, 30 seconds and one minute.

The Chicago-based content creator said: 'I thought it would be fun for people to know all the little nastiness that we don't think about every day.'

Despite the age-old adage of the five second rule, which posits that it is safe to eat something that has dropped on the floor as long as it's been picked up within five seconds - Aicher was shocked by the results.

In a video, which has garnered over 1million views, Aicher can be seen placing petri dishes on the floor for each time period and then storing the dishes in an incubator to see if bacteria grows.

After a certain period of time - Aicher doesn't specify how long - he observed the samples, all of which had some amount of bacteria growth on them, even the sample that was only on the ground for one second. 

White bacteria growths can be seen on the one-second petri dish and Aicher said: 'Looks like even zero seconds is too long.'

The sample that was on the ground for five seconds appeared to have roughly the same amount of bacteria as the one left for less than a second - debunking the myth that dropped food is safe to eat if picked up within five seconds. 

When he accidentally drops the five second sample, the video shows most of the bacteria transferring and sticking to the wooden table, furthering the spread of bacteria. 

Moving on, he shows the sample he put on the floor for 10 seconds has 'a bit more' growth, while those placed for 20 and 30 seconds have noticeably more bacteria.

However, the sample placed on the floor for one minute appeared to have a similar amount of bacteria to the five-second sample.

Nicholas added: 'Five seconds or 60, it'll be nasty either way.'

The experiment garnered nearly 20,000 likes on TikTok, where one viewer commented: 'Meh. I was doing the 5 second rule throughout my childhood and I'm still healthy.'

'The real factor is just how badly you don't want to waste what was dropped,' another user joked.

Someone else added: 'I'll pretend I didn't see this so I can keep blissfully doing the 5 second rule.'

'Never eating food from the floor again...' said one horrified user.

'Extra flavor,' quipped another viewer.

The floor - and even common kitchen surfaces - can be teeming with bacteria that can cause serious illness either 

Bacteria such as salmonella and listeria can immediately latch on and start to grow on food as soon as soon as it touches, leading to contamination. 

These bacteria then multiply on the dropped food and release toxins that can make you ill if you eat them. It is one of the main causes of foodborne illness. 

A salmonella infection can lead to typhoid fever, a serious disease that primarily affects the intestinal tract and can cause death if not treated properly. 

Similarly, a listeria infection can also cause to a range of complications, including sepsis (a severe reaction to infection that can cause organ damage), meningitis (inflammation of the brain and spinal cord) and in some cases, death

Symptoms of these conditions include upset stomach, nausea, vomiting, headache and diarrhea, which usually occur within 24 hours of eating contaminated food but can sometimes appear days to weeks later.

A shortness of breath, swelling and redness at the site of the infection, chest pain and rashes are also some signs of a bacterial infection. 

'Wet' foods - such as watermelon chunks, apples and deli meats - attract more bacteria faster than dry foods like chips or cookies. 

Every year, foodborne illness affects around 600 million people worldwide, including 48 million Americans.