# Dishwashing liquids with nuclease and protease: An improved biocompatible solution for the removal of adherent bacteria from fruits and vegetables

## TL;DR

Adding protease and nuclease enzymes to dishwashing liquid improves removal of bacteria from fruits and vegetables.

## Contribution

A novel biocompatible solution using protease and nuclease in dishwashing liquid for efficient removal of bacterial biofilms.

## Key findings

- Protease and nuclease mixtures reduced biofilm biomass of multiple bacteria species significantly.
- Enzyme-enhanced dishwashing liquid removed up to 99% of adherent bacteria from surfaces and produce.
- Treatment increased bacterial removal from vegetables up to 100-fold compared to standard liquid.

## Abstract

While plant food is an obligate part of human nutrition, vegetables and fruits are often contaminated by adherent foodborne pathogens, in turn requiring biocompatible solutions for their efficient elimination. We report the effect of proteinase (subtilisin) and nuclease (DNAse) additions to the dishwashing liquid for a more efficient removal of adherent bacteria and biofilms from glass surfaces and vegetables. The 15 min treatment with solely 0.06% protease solution decreased preformed biofilms of S. aureus and S. Typhimurium threefold, and treatment with 0.25% nuclease reduced them twofold, respectively. While nuclease itself was of low efficiency, the protease-nuclease mixture (0.06% of each protein) reduced the biomasses of biofilms of these bacteria fourfold, as well as biofilms of E. faecalis, E. coli, and K. pneumoniae twofold. The addition of enzymes to the dishwashing liquid increased the removal of Gram-negative bacteria from the glass 5–10-fold compared to basic liquid. Furthermore, enzymes enhanced the removal of adherent bacteria from lettuce, cucumber, celery, and apple up to 100-fold for S. aureus and E. faecalis and 20-fold for Gram-negative species, respectively, compared to the basic dishwashing liquid, as indicated by CFUs count and qPCR data. These data suggest that protease, both individually and especially in mixture with nuclease, is an attractive additive to dishwashing liquids to provide the removal of up to 99% of adherent bacteria from dishes, fruits, and vegetables.