Purpose: In this study anti-Salmonella activity of CM was determined for different CM concentrations and various environmental conditions in order to optimize its efficacy. Strain variation in CM sensitivity was examined, and genomic comparisons investigated genes and genotypes and their relationship to CM sensitivity.
Methods: Growth and survival of a three-strain S. enterica cocktail was determined by mean log CFU/ml ± standard deviation in water, pond water, artificial seawater (20 ppt), and nutrient broth with or without addition of various concentrations of CM at different pH (5,7,9) and temperature (25, 30, 37℃) combinations. Survival of various S. enterica strains and serotypes was compared under optimized conditions, and genomic sequences of these strains were processed by Bowtie, and Rapid Annotation Subsystem Technology in order to determine phylogenies and annotation of contig files.
Results: Optimum conditions for CM activity against S. enterica in water were pH7 and 37℃, but the effects of CM were significantly (P<0.0001) diminished by addition of NaCl, the presence of complex bacterial communities in pond water, and in stationary compared to log phase growth. S. enterica strains were non-detectable after 2 h exposure to 0.3% CM in sterile water, and significant reductions were seen with CM concentrations as low as 0.01% (P<0.001). Strains differences in CM sensitivity were observed and varied within serotype, while corresponding genotypes and predicted proteins were associated with increased sensitivity to CM.
Significance: This study provides conditions that may be useful for the application of CM as a sanitizer for irrigation and agricultural wash water.