Silver as Antibacterial Toward Listeria monocytogenes
In this study titled, “Silver as Antibacterial Toward Listeria monocytogenes,” published in Frontiers in Microbiology, in March 2016, researchers from the Department of Food Safety at the Istituto Zooprofilattico Sperimentale delle Venezie in Legnaro, Italy wrote: “Listeria monocytogenes is a serious food-borne pathogen that can contaminate food during processing and can grow during food shelf-life. New types of safe and effective food contact materials embedding antimicrobial agents, like silver, can play an important role in the food industry…In this context, the development of new types of safe and effective food contact materials able to extend the shelf life of food products or to prevent cross contamination is of great interest. Among different chemicals with antimicrobial activity, silver is considered as a good candidate, as it is known to exert antimicrobial properties toward both Gram positive and Gram negative bacteria.”
In the study, 20 different strains of Listeria monocytogens were tested. The researchers concluded that the silver was effective against all 20 strains: “This study aimed to investigate the effectiveness of silver in ionic and nano form as antimicrobial toward a panel of L. monocytogenes isolates. The results obtained showed that both chemical forms of silver exerted antimicrobial activity and should, therefore, be considered as suitable to be used as biocide against L. monocytogenes…The relation between the sensitivity assay and the amount of ions at the tested time points, in both cases (AgNPs and AgNO3) suggests that ions are the more effective elements exerting antibacterial activity…Our study suggests that L. monocytogenes is sensitive to silver and that the efficacy is linked to ionic release. We speculate that silver-based food contact materials could play a useful role in the food industry, perhaps to reduce surface contamination, or eventually, to prolong shelf life.”
In short, the researchers urged members of the food processing industry to look into using colloidal silver as an effective biocide against the Listeria monocytogenes food-poisoning pathogen.
