In 2018 and 2019, there were outbreaks of different strains of E. coli on romaine lettuce in the USA and Canada. In a new study, published in the journal Ultrasound in Medicine and Biology (https://www.umbjournal.org/article/S0301-5629(21)00052-1/fulltext), researchers used ultrasonically activated stream (UAS) to remove microbial contamination from spinach leaves obtained from the field and compared the results with leaves rinsed in plain water. The microbial loads on samples cleaned with and without UAS were enumerated and compared to unwashed samples on day 0 and day six after cleaning. Results showed that the microbial load on samples cleaned with UAS for 2 min was significantly lower on day six after cleaning than those treated without ultrasound. A cleaning duration of 2 min allowed sufficient time for UAS to disaggregate and detach the microbial contamination more effectively. The UAS cleaning did not produce significant surface damage. The treatment demonstrated the potential to extend the food shelf life of the leafy greens.
Ultrasonic cleaning of salad leaves could improve food safety