Investigation of the effect of washing on the growth of the bacteria on the eggshell
Eggs are a vital part of our diet. However, every year, 19,000 hospitalisations and 380 deaths are caused by Salmonella, a foodborne bacteria in poultry and eggs, alone in the United States (Centres for disease control and prevention, 2016). Our project is about the investigation on the effect of washing on the growth of bacteria on eggshells. In the experiment, we started by washing the eggs for a fixed amount of time before placing these eggs in the refrigerator for 24 hours. Next, we took cotton swab samples of each egg and spread it on separate agar plates, 8 in total. We incubated these agar plates by leaving it in the incubator for 24 hours. The results showed that the eggs that were not washed at all had the least amount of bacteria. Eggs already have a natural layer of protective coating called bloom, which helps to prevent bacteria from penetrating through the egg. When we wash the eggs, there is a chance of the bloom being washed off. Hence it is easier for the bacteria to enter the egg through the pores (M. P. 2005). From this, we can understand that washing our eggs might increase the chances of bacteria growing on the egg. With our experiment, we hope to educate users not to wash eggs as it promotes the growth of bacteria on eggs instead of preventing it.