Effects of organic acid alone and in combination with H2O2 and NaCl on Escherichia coli O157:H7: An evaluation of antioxidant retention and overall acceptability in Basil leaves (Ocimum basilicum)
2019
Valiolahi, Masome | Najafi, Mohamad Ali | Eskandani, Majid Alipour | Rahnama, Mohamad
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 °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.
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