Rapid Determination of Sanitizer Concentration Using Impedance-Based Methods

Abstract

Chlorine, iodophor, and quaternary ammonium solutions of various concentrations were assayed with rapid test kits and with three Bactometer impedimetric test codes (the impedance, conductance, and capacitance test codes). An initial study was conducted to determine which test code was most suitable for each sanitizer. Impedance was shown to be the best for sodium hypochlorite solutions, conductance for iodophor solutions, and capacitance for quaternary ammonium solutions. When Bactometer results were compared with test kit results, linear regression revealed strong correlations for all three sanitizer solutions. For sodium hypochlorite concentrations of 0 to 100 ppm and 100 to 1,000 ppm, R2 values of 0.87 and 0.99, respectively, were obtained. For iodophor concentrations between 25 to 150 ppm, an R2 value of 0.95 was obtained. For quaternary ammonium compound concentrations of 100 to 1,000 ppm, an R2 value of 0.94 was obtained. The impedimetric methods proved to be simple and rapid (6 min) alternatives for measuring concentrations of the sanitizer solutions with a high level of certainty (P < 0.0002). The Bactometer will save time when multiple samples are tested.

A review of conventional detection and enumeration methods for pathogenic bacteria in food

“…(Moore and Madden 2002). This technique requires specialized instrumentation with significant up-front costs, however, and necessitates the establishment of stringently reproducible growth curve profiles of isolated strains under each temperature or culture condition of interest (Duran and Marshall 2002). Variability may ensue from different food matrices containing inconsistent levels of interfering organic material and, as with the SPC, stressed bacteria may introduce an additional element of variability into experimental runs, making reproducibility difficult to achieve.…”

Analysis of total aerobic viable counts in samples of raw meat using fluorescence-based probe and oxygen consumption assay

“…Impedance based methods have included the Malthus, Bactometer, Rabit and Bactrac (Russell, 2000;Duran & Marshall, 2002;Sherry, Patterson, Kilpatrick, & Madden, 2006), and optical methods -VITEK (Odumeru et al, 1999) and MicroFoss (Odumeru & Belvedere, 2002). However, some tests, especially those requiring additional instrumentation, have been hampered by their complexity, high costs, limited applicability to and/or interferences by complex food samples.…”

Amplifier spurious input current components in electrode-electrolyte interface impedance measurements

“…In the latter reference, such drift effect is barely mentioned. Capacitive growth curves, for example, are used to assess the Minimum Inhibitory Concentration (MIC) of a disinfectant, where either appearance time or decrease to the 20% level is measured [13,14]. Reactance curves, instead of conductance, are more desirable because they show better sensitivity [9].…”