Inactivation of Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes in Orange and Tomato Juice Using Ohmic Heating

Abstract

The effects of ohmic heating on reduction of Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes in orange and tomato juice were investigated. Orange and tomato juice inoculated with E. coli O157:H7, Salmonella Typhimurium, and L. monocytogenes were subjected to ohmic heating with selected parameters including electric field strength from 10 to 20 V/cm and treatment times from 0 to 540 s. The number of pathogens was reduced by increasing the electric field strength from 10 to 20 V/cm as well as increasing treatment time. The population of E. coli O157:H7 was reduced more than 5 log after 120, 210, and 540 s of treatment in orange juice with 20, 15, and 10 V/cm electric field strengths, respectively. In tomato juice, levels of E. coli O157:H7 were reduced more than 5 log after 90, 180, and 480 s with the same electric field strengths. Similar phenomena were observed for Salmonella Typhimurium and L. monocytogenes, but E. coli O157:H7 was the most resistant to ohmic heating treatment. These results show that ohmic heating is potentially useful for inactivation of E. coli O157:H7, Salmonella Typhimurium, and L. monocytogenes and that the effect of inactivation depends on applied electric field strength, treatment time, pathogen species, and type of juice.

Effect of pH for inactivation of Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes in orange juice by ohmic heating

“…In general, reduction of E. coli O157:H7, S. Typhimurium and L. monocytogenes increased as ohmic heating temperature and treatment time increased in orange juice. These results are similar to those of Lee et al (2012) and Sagong et al (2011). In our study, the effect of inactivation was progressively greater as temperature increased at lower pH.…”

“…Newly spotlighted ohmic heating as an alternative to conventional heat treatment is effective due to not only the thermal effect of internal heat generation, but also the non-thermal effect of electropermeabilization (usually electroporation), which leads to enormous inactivation of microorganisms, especially foodborne pathogens. Several studies have been performed on inactivation by ohmic heating (Baysal & Icier, 2010;Lee et al, 2012;Park & Kang, 2013;Sagong et al, 2011). Park and Kang (2013) demonstrated the effect of electroporation by ohmic heating for inactivation of foodborne pathogens by comparing conventional heating with ohmic heating.…”

“…Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes are important pathogens that can cause serious foodborne illnesses (Linton, McClemens, & Patterson, 1999;Sagong, Park, Choi, Ryu, & Kang, 2011). E. coli O157:H7 can survive well in acidic foods and beverages because it tolerates some organic acids and has acid-adaptability (Koodie & Dhople, 2001;Mazzotta, 2001).…”

Effect of Frequency and Waveform on Inactivation of Escherichia coli O157:H7 and Salmonella enterica Serovar Typhimurium in Salsa by Ohmic Heating

“…Although numerous research studies of ohmic heating inactivation of microorganisms have been reported (28)(29)(30)(31), to our knowledge there is no information concerning the inactivation of E. coli O157:H7, and S. Typhimurium in solid-liquid food mixtures using high-frequency ohmic heating. The treatment time required to reduce E. coli O157:H7 and S. Typhimurium to below the detection limit (1 log CFU/g) decreased as the frequency increased.…”

Fate of Listeria monocytogenes and Salmonella Typhimurium during spontaneous cauliflower fermentation

“…Regarding the latter, the comparative ability of several L. monocytogenes and Salmonella spp. strains to survive under various interventions has been extensively studied in both laboratory media and foodstuffs (Carpenter, Smith, & Broadbent, 2011;Gomez-Aldapa et al, 2011;Menz, Vriesekoop, Zarei, Zhu, & Aldred, 2010;Nightingale, Thippareddi, Phebus, Marsden, & Nutsch, 2006;Porto-Fett et al, 2008Sagong, Park, Choi, Ryu, & Kang, 2011;Tiganitas, Zeaki, Gounadaki, Drosinos, & Skandamis, 2009). In the present study L. monocytogenes strain under study seemed more capable in surviving than S. typhimurium strain, especially at low and medium initial inocula, whereas no significant differences in the survival at high initial inocula were observed.…”