Reducing a Pathogen of Public Health Concern through Application of Elevated Hydrostatic Pressure
With tremendous ability of plethora of microorganisms to move towards fitness through vertical and horizontal gene transfer mechanisms, prevention of natural and anthropogenic pathogens of public health concern is a daunting task and a moving target. Elevated hydrostatic pressure is a non-thermal procedure that exposes pathogens to pressures of up to 80,000 PSI (>550 MPa). Various serovars of Salmonella are one of the leading causes of diarrheal diseased both nationally and internationally. In 2013, Centers for Disease Control and Prevention had also categorized non-typhoidal Salmonella as a “serious threat” to the public health due to persistence of various multidrug resistant phenotypes of the bacterium in environmental and healthcare facilities. The current study discusses laboratory challenge studies for
inactivation of the pathogen exposed to various time and intensity levels of elevated hydrostatic pressure. Studies are randomized complete block designs, analyzed statistically using GLM procedures of SAS9.2 software at type one error level of 5%. A Barocycler Hub440 unit (Pressure BioScience Inc., South Easton, MA), equipped with a water jacket and circulating water bath for precise application of hydrostatic pressure and controlled temperature was utilized. Five outbreak associated strains of Salmonella were used in this study. Up to 0.7 and 6.2 log reductions (P<0.05) of habituated Salmonella serovars at planktonic stages were achieved using application of pressure at 379 MPa for 30 seconds and 8 minutes, respectively. Similar reductions were observed for lower intensity levels of 310 MPa, and 241 MPa with 0.5 to 4.2 and 0.8 to 1.6 log reductions, respectively. Results of this study could be incorporated as a part of predictive public health microbiology modeling and risk assessment analyses for prevention of Salmonellosis episodes.