Bacteria in Household Sponges: A study testing which physical methods are most effective in decontaminating kitchen sponges

This study was undertaken to determine the effectiveness of various physical methods for decontaminating kitchen sponges. Sponges were distributed to participants to be used in the home on a daily basis, after which time they were collected for analysis. Bacterial concentrations were determined using the spectrophotometer. A sample from each sponge was submerged in nutrient broth, and incubated for 48 hours at 37 ̊C. Once the samples had been incubated the nutrient broth was tested for optical density. The sponges were then cleaned using several physical tests, which included microwaving at 30 or 60 seconds, boiling, dishwashing, and washing in the washing machine. The dishwasher had the largest bacterial reduction, reducing bacteria by 57.3%, followed by boiling, with an average bacterial reduction of 47.2%, and the washing machine with an average bacterial reduction of 43.2%. Thirty seconds and 60 seconds of microwaving had no statistically significant reduction compared to the uncleaned control. The results of my study suggested that high temperature in combination with washing is more effective in reducing bacteria in kitchen sponges than using heat alone.