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Table 2 Minimum inhibitory concentration of the natural and organic antimicrobials against L. monocytogenes, E. coli O157:H7, and S. enteritidis at pH 7.1

From: Efficacy assessment of various natural and organic antimicrobials against Escherichia coli O157:H7, Salmonella enteritidis and Listeria monocytogenes

Tested compound Tested range Minimum inhibitory concentration in ppm
L. monocytogenes E. coli O157:H7 S. enteritidis
pH 7.1 pH 7.1 pH 7.1
Thymol 0–300 200 ppm 25 ppm 25 ppm
Salicylic acid 0–500 500 ppm 500 ppm 500 ppm
Acetylsalicylic acid 0–500 500 ppm 500 ppm 500 ppm
Benzoic acid 0–300 200 ppm 300 ppm 200 ppm
Sodium benzoate 0–300 300 ppm 300 ppm 300 ppm
3-t-butyl-4-Hydroxyanisole 0–300 300 ppm 300 ppm 300 ppm
Ibuprofin 0–300 50 ppm 50 ppm NA
4-Acetamidophenol 0–300 NA NA NA
  1. Different concentrations of each antimicrobial were each added to 10-ml tryptone soya broth tubes and then inoculated (50 μl) of an overnight culture of the bacterial suspension. Tubes were incubated at 37 °C for 24 h. Negative and positive controls were performed. The optical density of each tube was measured using a spectrophotometer. Minimum inhibitory concentration is the lowest concentration of the assayed antimicrobial agent that inhibits the visible growth
  2. NA not applicable