Last week, Dr Rhys Grant from our Programme collaborated with Dr Sio Ball from the Department of Biochemistry to run a summer school project for students taking part in the Clifton Scientific Trust UK-Japan Young Scientists Workshop.
The project saw A-level students from the UK and Japan working together to investigate the 'five-second rule' – that it is OK to consume food that has fallen onto the floor so long as it is picked up again within five seconds. Students first had to scientifically drop food (at its best-before-end date and which would otherwise have gone to waste) onto various floor surfaces, leaving it there for times both shorter and longer than the magical five seconds, and then culture any contaminating bacteria overnight across a range of growth media. The following day, bacterial load (the number of bacteria colonies) was scored and bacteria were then assayed for different traits, such as innate antibiotic resistance, antibiotic production, and quorum sensing (the process through which bacteria 'talk' to one another). Additionally, a selection of the colonies were analysed by gram staining and microscopy to differentiate samples based on the chemical and physical properties of their cell walls. The students worked extremely hard, and, as a class, over 1,500 data points were obtained after just 2.5 days in the lab.
To end their week in Cambridge, the students presented their results to their peers, project facilitators, scientists, and a number of distinguished guests, including the President of Barclays Bank Japan, the Chief Executive of the Great Britain Sasakawa Foundation, and a former Director of the Royal Greenwich Observatory, at the Workshop Presentation Day at Murray Edwards College. Perhaps unsurprisingly, the five-second rule turned out to be a myth, with food being contaminated even after only brief contact with all of the floor surfaces tested and no significant difference in the bacterial load observed between contact times that were shorter or longer than five seconds. However, the results did suggest that moist foods, such as chicken and jelly, pick up far more bacteria than dry foods like chocolate, so, depending on the floor, a dropped custard cream may be salvageable!
The students did exceptionally well throughout the week; learning to communicate across language and cultural barriers, picking up second year undergraduate-level scientific knowledge and practical skills almost instantaneously, and delivering a presentation with the clarity and confidence of professionals. We hope this is the beginning of some fantastic future careers in science for these students and wish them all the best for their future studies.
