Effect of culture method on storage, plasma, and dry heat treatment resistance of Salmonella enterica serovar Typhimurium on black pepper.

ABSTRACT

The purpose of this study was to determine the effect of the culture method on the resistance of Salmonella Typhimurium in low water activity foods to storage, plasma, and dry heat. Whole black peppers were used as the model food. S. Typhimurium cultured in liquid broth (tryptic soy broth) or solid agar (tryptic soy agar) and inoculated on whole black pepper was stored or treated with cold plasma or dry heat. Inactivation of S. Typhimurium cultured in liquid medium was higher in all the treatments. Liquid-cultured S. Typhimurium showed higher DPPP = O (diphenyl-1-pyrenylphosphine oxide) values compared to the solid-cultured S. Typhimurium after plasma or dry heat treatment. Furthermore, the unsaturated fatty acid and saturated fatty acid ratio (USFA/SFA) was significantly (P < 0.05) reduced from 0.41 to 0.29 when S. Typhimurium was cultured on solid agar. These results suggested that the use of food-borne pathogens cultured on solid agar is more suitable for low water activity food pasteurization studies.