Scientists investigate the validity of the three second rule with varying results
We have all done it, eaten something that has fallen on the floor and then tell ourselves that it is okay as long as it was not on the floor for more that three seconds. Even then some people will stretch that age old law to 5 seconds depending as to how much they want the tasty morsel they inadvertently dropped on the floor.
The whole premise of the rule is based on the length of time the food has been on the floor and that it could not possibly have been there long enough to be contaminated with bacteria and other nasty things that live down there in the world beneath our feet.
The Mail Online reports that there has been no research of any substance into this matter until now. Scientists at the Manchester Metropolitan University have investigated this the three second theory to test its validity, fact or fiction. Five food items; bread with jam, cooked pasta, ham, a biscuit and dried fruit have been used to conduct the experiment. They are all commonly eaten foods and have differing water activity levels, which is a key factor in sustaining bacterial growth within the three second rule.
They were all dropped on the floor for varying time intervals, three, five and ten seconds.
The experiment revealed different results for each of the different food types with salt and sugar being the key determining factor.
The foods with a high salt or sugar content were safer to eat as it is more difficult for bacteria to survive. This leads to the startling revelation that processed foods that have been dropped on the floor are a lot safer to eat due to the high salt and sugar levels used in flavouring and preserving them.
The ham (high salt) and the bread and jam (high sugar) performed very well and after three seconds on the floor showed little sign of bacterial growth. Ham is a processed meat preserved with salt and nitrates which prevents the growth of most bacteria. The bread and jam showed no bacterial growth after time on the floor, which can be linked to the high sugar content of the jam which makes it unlikely to support microbial growth.
The dried fruit and pasta however showed signs of klebsiella after three seconds. Klebsiella, named after the German microbiologist Edwin Klebs, is a bacteria which has the potential to cause pneumonia, urinary tract infections, septicaemia and soft tissue conditions.
The dried fruit and pasta also had increased yeast counts
The biscuits proved safe after ten seconds due to their low water content with the technical office on the team Kathy Lees saying, ‘No specific organisms were detected on the biscuit, which has a low water activity level and low adhesion ability.