“Streams of water carrying sound and microscopic air bubbles can remove microbial contaminants from spinach leaves, according to a study.
Scientists used acoustic water streams to clean spinach leaves sourced from a field crop, then compared results with leaves rinsed in plain water at the same velocity.
Salad and leafy green vegetables may be contaminated with bacteria during growing, harvesting, preparation and retail, leading to foodborne outbreaks that may be fatal. There is no cooking process to reduce the microbial load in fresh salads and other fresh produce dishes so washing by the supplier and consumer is vital.
Washing with soap, detergent, bleach or other disinfectants is not recommended and the crevices in the leaf surfaces mean washing with water may leave behind an infectious dose. Chemicals may also not penetrate the crevices.
Results, published in the journal Ultrasound in Medicine and Biology, showed the microbial load on samples cleaned with ultrasonically activated stream (UAS) for two minutes was significantly lower on day six after cleaning than on those treated without ultrasound.
Cleaning for two minutes also did not produce significant surface damage, which can affect overall leaf quality, according to the research.”