Effects of organic acid alone and in combination with H2O2 and NaCl on Escherichia coil O157:H7: An evaluation of antioxidant retention and overall acceptability in Basil leaves (Ocimum basilicum)

摘要

In this study, the efficacy of household sanitizers application on reduction of Escherichia coli O157:H7, ascorbic acid, total phenolics, DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging and overall acceptability of inoculated fresh basil leaves (Ocimum basilicum), at temperature of 40 degrees C was investigated. Sanitizers containing lactic acid (LA), acetic acid (AA) and citric acid (CA) were used at concentration of 2%, individually or in combination with H2O2 (1% or 2%), and NaCl (7%). Control a and b were unwashed and washed leaves with distilled, deionized and sterilized water, respectively. All sanitizing treatments, in comparison to the control a, reduced the numbers of E. coli O157:H7 (0.24 +/- 0.12-3.37 +/- 0.48 log CFU/g) at day 1 (1 h after sanitizing). The lowest number of E. coli O157:H7 population (2.35 +/- 0.26 log CFU/g) was observed by applying the LA + H2O2 (%2) treatment at first day of chilled storage. The highest amount of ascorbic acid (27.77 +/- 0.06 mg/100 g), total phenolic (112.2 +/- 0.5 mg gallic acid equivalents/100 g) and DPPH radical scavenging activity (95.2 +/- 0.5%) was observed in control a at first day (P & 0.05). The results showed that the amount of ascorbic acid, total phenolics, DPPH radical scavenging activity and overall acceptability of basil leaves decreased during chilled storage. On day 2 of storage, the scores of sensory attributes for the control group were less than the minimum score of acceptance (i.e. 5 points). The results of this study indicated that LA + H2O2 (2%) treatment rendered the samples favorable in terms of overall appearance (&= 5) up to 48 h.