Inactivation of stressed Escherichia coli O157:H7 in tahini (sesame seeds paste) by gamma irradiation. (November 2016)

• Record Type: Journal Article
• Authors: Osaili, Tareq M.; Al-Nabulsi, Anas
• Is Part Of: Food control. Volume 69(2016:Nov.)
• Page Start: 221
• Page End: 226
• Publication Date: 2016-11
• Subjects: Gamma irradiation -- Stresses -- Escherichia coli O157:H7 -- Tahini; Food -- Quality -- Periodicals; Food -- Analysis -- Periodicals; Food handling -- Periodicals; Food industry and trade -- Quality control -- Periodicals; Aliments -- Industrie et commerce -- Qualité -- Contrôle -- Périodiques; Aliments -- Qualité -- Périodiques; Aliments -- Analyse -- Périodiques; Hygiène alimentaire -- Périodiques; Food -- Analysis; Food handling; Food -- Quality; Periodicals; Electronic journals; 664.07
• DOI: 10.1016/j.foodcont.2016.05.009
• Languages: English
• ISSNs: 0956-7135

Abstract

Abstract: Tahini, sesame seeds paste, is of great concern to both regulatory agencies and food processors as it may be exposed to microbial contamination through processing. This study aimed to evaluate the effect of gamma irradiation on inactivation of stressed Escherichia coli O157:H7 and microbiota in tahini, and on the color and peroxide, p-anisidine, and acid values of tahini. Tahini samples were inoculated with a cocktail of 4 strains of unstressed or stressed (heat, cold, starvation, salt, acid, alkaline or ethanol stress) E . coli O157:H7 and exposed to gamma irradiation for up to 1.0 kGy. The D10 -values of unstressed and stressed cells ranged from 0.31 to 0.39 kGy. Stresses (except for starvation) reduced the irradiation resistance of E . coli O157:H7 significantly ( P < 0.05) in tahini. Irradiation dose of 1 kGy reduced inoculated E . coli O157:H7 and microbiota in tahini by 2.6–3.2 log10 CFU/g and 1.6 log10 CFU/g, respectively, and did not affect ( P > 0.05) tahini quality (color and oxidative rancidity). Irradiation might be used as an effective means of eliminating E . coli O157:H7 and other foodborne pathogens with similar irradiation resistance, if present, in tahini in post-packaging situation without compromising the quality. Highlights: D10 -values of stressed Escherichia coli O157:H7 in tahini ranged from 0.31 to 0.39 kGy. 1 kGy gamma ray did not affect the color, peroxide, p-anisidine and acid values of tahini. 1 kGy gamma ray reduced microbiota in tahini by 1.6 log10 CFU/g.