Jan. 1, 2014 - Dec. 31, 2014Award Number
Center for Produce SafetyAmount Awarded
Massimiliano Marvasi, Ph.D.
University of Florida
Eric S. McLamoreSummary
Biofilms formed on industrial surfaces in post-harvest production facilities are recalcitrant reservoirs of pathogens, which are difficult to control. Pathogens in biofilms are resistant to common disinfectants and can contaminate produce during post-harvest handling. Even though mechanical removal of biofilms is one of the most common methods for controlling them in the production facilities, this approach is only partially effective and only removes biofilms that are easily accessible. Therefore, novel approaches for controlling biofilms are needed. We will test how effectively hydrogels containing Nitric Oxide Donors disperse biofilms under the conditions that mimic production environment and increase sensitivity of the dislodged biofilms to quaternary ammonium salts or chlorine dioxide. Four compounds will be tested at nano- to picomolar concentrations to determine how effectively they dislodge biofilms (individually or in combination with disinfectants or detergents) formed by mixtures of Salmonella, Listeria or E.coli and Leuconostoc. Upon completion of this feasibility study, we expect to have identified nitric oxide donors that are capable of dislodging existing biofilms. We envision that further studies will focus on designing foaming agents containing these molecules for dislodging biofilms from surfaces in post-harvest facilities prior to their cleaning with common disinfectants.
Biofilms formed on industrial surfaces in post-harvest production facilities are particularly problematic. Biofilms serve as recalcitrant reservoirs of pathogens and are difficult to control. While there are several innovative strategies for reducing microbial attachment to the surfaces of industrial significance, the tool-set for disrupting existing biofilms is significantly less versatile. Recent discoveries of the function of nitric oxide in dispersing existing biofilms offer an opportunity to test the feasibility of using this gas in industrial applications. The rationale for this approach is offered by the studies that demonstrate that nitric oxide “donor” molecules (NODs) significantly decrease surface areas of biofilms under the laboratory conditions. More than 105 NODs are currently available, but only few of them were tested on enteric pathogens; fewer yet were explored for the potential industrial applications. If proven effective in dispersing biofilms formed on industrial surfaces in post-harvest facilities, we see several potential cost-effective applications for disrupting biofilms. The dual action of the NOD more the disinfectant can be significant: while NO proceed to the dispersion of the biofilm, disinfectant can easily kill planktonic cells. Therefore, with this one-year pilot study, four non-toxic NODs and their mixtures with disinfectants and detergents will be tested to determine efficacy of these compounds in dispersing biofilms and disrupting attachment of mixtures of Salmonella enterica, pathogenic E. coli, Listeria and Leuconostoc to polypropylene, polystyrene and stainless steel when associated with quaternary ammonium salts and chlorine dioxide.