METHOD FOR APPLYING BACTERICIDAL SOLUTIONS

Abstract: The invention relates to method for applying electrochemically activated, bactericidal aqueous solution in the bactericidal treatment of a contaminated medium, the method characterised in including the step of atomising and dispersing the electrochemically activated, bactericidal aqueous solution into the atmosphere about a contaminated medium to be treated, forming a fog of airborne droplets of between 1 and 100 micrometers of suitable bactericidal concentration about the treated medium.

Description: METHOD FOR APPLYING BACTERICIDAL SOLUTIONS TECHNICAL FIELD This invention relates to a method for applying bactericidal solutions in the bactericidal treatment of contaminated produce, apparatus and surfaces. BACKGROUND ART The application of bactericidal solutions in the bactericidal treatment of contaminated produce, equipment and surfaces is usually carried out by means of washing, with solutions such as chlorine solutions, etc. or by means of steaming. However, total wetting during washing and/or high temperatures during steaming are often disadvantageous in that they are unacceptable and even detrimental to the produce, apparatus and/or surfaces. For purposes of this application the term "medium" shall include produce, apparatus and surfaces and cognate terms shall have similar meanings. OBJECTIVES OF THE INVENTION It is accordingly an object of this invention to produce a method and equipment for applying bactericidal solutions that will overcome the above disadvantages. DISCLOSURE OF INVENTION According to a first aspect of the invention there is provided a method for applying electrochemically activated, bactericidal solution to a contaminated medium to be treated, including the step of atomising and dispersing the solution into the atmosphere about a contaminated medium to be treated, forming a fog of airborne droplets of between 1 and 100 micrometers of suitable bactericidal concentration about the treated medium. The electrochemically activated, bactericidal aqueous solution may be selected from a group consisting of anion-containing and cation-containing solutions. The electrochemically activated, bactericidal aqueous solution may be prepared by means of electrolysis of an aqueous solution of a salt. The salt may be sodium chloride. In particular, it may be non-iodated sodium chloride or potassium chloride. The anion-containing solution and the associated cation-containing solution may be produced by an electrochemical reactor or so-called electrolysis device having a through flow electrochemical cell with two co-axial cylindrical electrodes, with a co-axial diaphragm between the two electrodes so as to separate an annular inter-electrode space into a catalytic and an analytic chamber. The anion-containing solution is referred to hereinafter for brevity as the "anolyte solution" or "anolyte" and the cation-containing solution is referred to hereinafter for brevity as the catholyte solution" or "catholγte". The anolyte solution may be produced from an about 3 to 1 0% aqueous NaCl solution, electrolysed to produce mixed reductant and mixed oxidant species. These mixed reductant and oxidant species may be labile and after about 96 hours the various oxidant and reductant species may disappear with relatively no residues being produced. The anolyte solution may have a suitable redox potential, preferably of about between + 450 mV and + 1 200 mV and may have a suitable pH, preferably of between 2 and 9 for bactericidal treatment of a specific medium. The anolyte solution may include mixed oxidant species such as CIO; CIO ; HclO; OH ; HO 2 " ; H 2 O 2 ; O 3 ; S 2 O 8 2" and CI 2 O 6 2 \ The catholyte solution may have a suitable pH, preferably of between about 1 2 and 1 3, and a suitable redox potential, preferably of between about -200 mV and -900 mV, for bactericidal treatment of a specific medium. The catholyte solution may include reductant species such as OH " ; H 3 " ; 0 2 ; H 2 -; H0 2 ; H0 2 " and 0 2 " . The method may include the preliminary step of enclosing the contaminated medium to be treated in a closed volume prior to atomising and dispersing the solution into the closed volume. The atomising and dispersing step is preferably repeated at pre-determined intervals so as to maintain a suitable fog concentration in the closed volume, thus utilising the microcidal and other properties of the electrochemically activated solution without detrimentally affecting the quality and condition of the produce, such as reducing dehydration and weight loss, the equipment and/or the surfaces to be treated. According to a second aspect of the invention there is provided equipment for use in a method for applying electrochemically activated, bactericidal aqueous solution as hereinbefore defined, the equipment including an electrolysis device having a through flow electrochemical cell with two co¬ axial cylindrical electrodes, with a co-axial diaphragm between the two electrodes so as to separate an annular inter-electrode space into a catalytic and an analytic chamber; and means for atomising and dispersing the solution into the atmosphere about a contaminated medium to be treated. BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment of the invention will now be described by means of non-limiting examples only. Example 1 : Multiple fogging cycles were used so as to determine the efficacy thereof on the total bacterial surface loads in a series of chillers over a 42 hour chilling period. Samples 1 , 2 and 3 were carcasses fogged separately in closed chillers with 30 minute intervals. Samples 4 and 5 were carcasses sampled in operating chillers. Foggers were put on the floor of the chillers and carcasses were therefore not fogged directly. 3 x sampling was conducted 42 hours after the previous fogging on all samples so as to establish whether there would be an increase in bacterial loads over the 42 hours prior to de-boning. Multiple fogging in areas where the fog is not mechanically removed from the room during the fogging process is highly effective in reducing total counts. Fogging in operating chillers is not effective. Throughout the trial Coliform counts were low, most probably due to carcass washing and results therefore were not given. The results are shown in the accompanying tables. Example 2 : Enclosed volumes containing diverse equipment, including 2 tables and a scale, were fogged so as to determine the microcidal effect of anolyte on the enclosure surfaces and the enclosed equipment. The results are shown in the accompanying tables. Example 3 : Cattle carcasses were treated at the Agricultural Research Council Unit, Irene, Gauteng, South Africa. The anolyte used was generated under and with the following characteristics : Current : 10 Ampere; Voltage : 24 Volt ORP : + 762 mV; TDS; 6,04 g/£ pH : 6,8 The chiller treated had volume (space) for about 1 6 carcasses. The fogging process consisted of 3 cycles of 20 minutes each, with 10 minutes in between each cycle. Samples were taken from the neck area, the breast area, the back area and the hindquarter area. Samples were taken of all micro-organisms by means of total plate count ( Redoc plates), total plate counts (petri film) and Coliforms (petri film). The results are shown in the accompanying tables. Example 4 : A number of 800 lamb carcasses were subjected to tests, 400 being fogged with anolyte and 400 being used as the control group. Samples were taken before treatment, after a second cycle and a fourth cycle, while the control group was sampled before and after 24 hours of chilling. Additional samples were taken from both the treated and the control group for measuring TPC only. The results are shown in the accompanying tables. It will be appreciated that many variations in detail are possible without departing from the scope and/or spirit of the invention as claimed in the claims hereinafter. Example 1: (New Style Pork) Objective: To determine the effect of multiple fogging on the total bacterial -surface loads over a 42 hour chilling period. Comments 1, 2 and 3 were fogged separately in chillers with 30 minutes intervals. Chillers were not in operation. After fogging, carcasses were returned to original chillers. Example 2 : Microcidal Effect of Anolyte on Surfaces and Equipment Example 3: (Calf Carcasses) A. Trial Carcasses Direct fogging in chiller with interrupted air circulation during the fogging process Comments: The fourth Swab was on the side of the triceps cut where all carcasses had been pushed by hand and were therefore more contaminated than adjoining surfaces. All swabs were incubated at 37° C for 48 hours Coliform counts were negligible on all carcasses B. Negative Control : Indirect fogging of carcasses that were present in the chiller, during the time of the experiment. Only final carcass counts on similar locations as the trials were taken. Example 4: Woolworths Trial 800 lamb carcasses Results: Treatment with Anolvte Control group: Further swabs were taken on the shoulder of 5 chilled and fogged carcases (after the 4 th fogging). Carcase # TPC 4BS1 1 4BS2 3 4BS3 0 4BS4 6 4BS5 6 Total 16 Mean/20cm 2 3.2

Claims: CLAIMS . A method for applying electrochemically activated, bactericidal aqueous solution in the bactericidal treatment of a contaminated medium, the method characterised in including the step of atomising and dispersing the electrochemically activated, bactericidal aqueous solution into the atmosphere about a contaminated medium to be treated, forming a fog of airborne droplets of between 1 and 100 micrometres of suitable bactericidal concentration about the treated medium. 2. A method as claimed in claim 1 wherein the aqueous solution is selected from a group consisting of mixed oxidant, anion-containing and mixed reductant, cation-containing solutions. 3. A method as claimed in claim 2 wherein the electrochemically activated, bactericidal aqueous solution is prepared by means of electrolysis of an aqueous solution of a salt. 4. A method as claimed in claim 3 wherein the salt is selected from the group consisting of sodium chloride or potassium chloride. . A method as claimed in claim 2 wherein the anion-containing solution and the cation-containing solution is produced by an electrolysis device, having a through flow electrochemical cell with two co-axial cylindrical electrodes, with a co-axial diaphragm between the two electrodes so as to separate an annular inter- electrode space into a catalytic and an analytic chamber. 6. A method as claimed in claim 2 wherein the electrochemically activated, bactericidal aqueous solution is produced from an about 3 to 10% aqueous NaCl solution, electrolysed to produce mixed reductant and mixed oxidant species. 7. A method as claimed in claim 6 wherein the mixed oxidant and reductant species are labile and, after about 96 hours, disappear with relatively no residue being produced. 8. A method as claimed in claim 2 wherein the anion-containing solution having a redox potential of about between + 450 V and + 1 200 mV and the cation-containing solution having a redox potential of about between -200 mV and -900 and wherein the anion-containing solution has a pH of between 2 and 9 and the cation-containing solution has a pH of 1 2 and 1 3. 9. A method as claimed in claim 2 wherein the anion-containing solution includes mixed oxidant species selected from the group consisting of CIO; CIO ; HclO; OH ; HO 2 ; H 2 O 2 ; O 3 ; S 2 O 8 2" and cι 2 o 6 2 -. 10. A method as claimed in claim 2 wherein the cation-containing solution includes mixed reductant species selected from the group consisting of OH " ; H 3 " ; 0 2 ; H 2 -; H0 2 -; H0 2 " and 0 2 . 1 1 . A method as claimed in claim 1 wherein the atomising and dispersing step is repeated at pre-determined intervals so as to maintain a suitable bactericidal fog concentration in the atmosphere, thus uitilising the microcidal properties of the electrochemically activated solution without detrimentally affecting the quality and condition of the contaminated medium to be treated. 1 2. Equipment for use in a method for applying electrochemically activated, bactericidal aqueous solution in the bactericidal treatment of a contaminated medium to be treated, the equipment including an electrolysis device, having a through flow electrochemical cell with two co-axial cylindrical electrodes, with a co-axial diaphragm between them so as to separate an annular inter-electrode space into a catalytic and an analytic chamber; and means for atomising and dispersing the solution into the atmosphere about a contaminated medium to be treated.

Inventors: HINZE GILBERT THEO, HINZE, GILBERT, THEO
Applicants: HINZE GILBERT THEO, RADICAL WATERS PTY LIMITED, HINZE, GILBERT, THEO, RADICAL WATERS (PTY) LIMITED
Application year: 1999
Main classification: A61L2
IPC codes: A23B4, A23G7, A23G9, A23L3, A61L2