Inactivation of Salmonella spp., Escherichia coli O157:H7 and Listeria monocytogenes in Tahini by Microwave Heating

• Published in: Foods Vol. 10; no. 12; p. 2972
• Main Authors: Osaili, Tareq M., Al-Nabulsi, Anas A., Al Sheikh, Yasmeen M., Alaboudi, Akram R., Olaimat, Amin N., Al-Holy, Murad, Al-Rousan, Walid M., Holley, Richard
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 02.12.2021; MDPI
• Subjects: Anisidine; color; D-value; Deactivation; Desiccation; E coli; Escherichia coli; Escherichia coli O157; Food; Food science; Heat treatment; Heat treatments; Heating; Inactivation; Listeria; Listeria monocytogenes; Microorganisms; microwave; Microwave cooking; Microwave heating; microwave treatment; Ovens & stoves; pathogen survival; Pathogens; Product recalls; risk; Salmonella; Seeds; sesame paste; Starvation; Traditional foods; United Kingdom > UK; Canada; desiccation; starvation; D-value; microwave; sesame paste
• ISSN: 2304-8158; 2304-8158
• DOI: 10.3390/foods10122972

Tahini (sesame paste) is a traditional food. Numerous foodborne outbreaks have been associated with it. This study aimed to (i) explore the efficiency of 2450 MHz microwave heating at 220, 330, 440, 550, and 660 W on the inactivation of Salmonella spp, Escherichia coli O157:H7, and Listeria monocytogenes in tahini; (ii) determine the impact of desiccation and starvation stresses on pathogen survival; (iii) assess the impact of microwave heating on the physicochemical characteristics of tahini. The inoculated microorganisms in tahini were reduced with higher microwave power levels (p < 0.05) and longer exposure times. The D-values of unstressed Salmonella spp., Escherichia coli O157:H7, and L. monocytogenes ranged from 6.18 to 0.50 min, 6.08 to 0.50 min, and 4.69 to 0.48 min, respectively, at power levels of 220 to 660 W, with z-values of 410, 440, and 460 W, respectively. Generally, desiccation and starvation stress levels prior to heating increased microbial resistance to heat treatment. Microwave heating did not affect acid, peroxide, p-anisidine, or color values of tahini up to 90 °C. These findings reveal microwave heating as a potential method for lowering the risk of Salmonella spp., E. coli O157:H7 and L. monocytogenes in tahini with no compromise on quality.