Effect of high hydrostatic pressure and pressure cycling on a pathogenic Salmonella enterica serovar cocktail inoculated into creamy peanut butter.
The ability of Salmonella enterica serovars to survive in high fat content, low water activity foods like peanut butter has been demonstrated by large foodborne illness outbreaks in recent years. This study investigates the potential of high hydrostatic pressure processing, including  pressure cycling, to inactivate Salmonella inoculated into creamy peanut butter. A cocktail of pathogenic strains of Salmonella Enteritidis PT30, Salmonella Tennessee, Salmonella Oranienburg, Salmonella Anatum, Salmonella Enteritidis PT 9c, and Salmonella  Montevideo obtained from peanut butter- and nut-related outbreaks was inoculated (10(6) to 10(7) CFU/g) into creamy peanut butter and high pressure processed under five different sets of conditions, which varied from 400 to 600 MPa and from 4 to 18 min. The log CFU  reductions achieved varied from 1.6 to 1.9. Control experiments in which Salmonella was inoculated (10(9) CFU/g) into 0.1% peptone buffer and high pressure processed at 600 MPa for 18 min showed inactivation to below the detection limit of 100 CFU/g, confirming that high pressure  processing is effective at destroying Salmonella in high-moisture environments. Pressure cycling under three sets of conditions consisting of pressures from 400 to 600 MPa, 3 to 10 pressure cycles, and hold times of 6 min for each cycle showed reductions similar to those seen in noncycling  experiments. The results of our experiments suggest that the peanut butter food matrix facilitates the survival of Salmonella when exposed to high hydrostatic pressure processing.
Department of Food Science, Rutgers-The State University of New Jersey, New Brunswick, New Jersey 08901, USA.
Tanya
T
D'Souza
Mukund
M
Karwe
Donald W
DW
Schaffner
D010367:Arachis / Q000382:microbiology*; D015169:Colony Count, Microbial; D005506:Food Contamination / Q000032:analysis / Q000517:prevention & control; D005516:Food Microbiology; D005519:Food Preservation / Q000379:methods*; D006801:Humans; D006874:Hydrostatic Pressure; D050296:Microbial Viability; D019779:Salmonella enterica / Q000254:growth & development*