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 c-axial cylindrical electrodes, with a c-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"catholyte".

The anolyte solution may be produced from an about 3 to 10% aqueous NaCI 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 + 1200 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; ClO-; HclO; OH-; HO2-; H202; 03; S2°82 and C1206-.

The catholyte solution may have a suitable pH, preferably of between about 12 and 13, 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- ; H3- ; 02; H2; HO2; H02-and 02.

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 c-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: Enclose 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 enclose 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/t pH: 6,8 The chiller treated had volume (space) for about 16 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.

Example4: 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. Colony Forming units/lOcm Anolyte production Fogging frequency Efficacy Parameters 1 No. Control lx 2x 3x (+36h) % Red. Log red. Amp pH 169 TNTC 12 5 7 99.9-6 9 6. 66 236 TNTC 360 3 1 99.9-6 9 6.66 168 600 6 3 1 99.9-2 246 110 120 2 1 99.9-2 24V 170 13 3 70 0 99.9-1 1. 0 Bar 99.7-3.4 2 189 12 7 1 30 0 0 12 6.8 203 100 8 15 0 99.9-2 200 140 13 1 0 99.9-2 192 80 2 35 2 97.5-1 24V 232 200 6 80 0 99.9-2 1. 0 Bar 79.4-1.4 3 193 TNTC 100 3 2 99.9-6 10 5.0 177 2 30 20 10 0 0 178 110 70 50 24 78.2-1 179 13 10 6 1 92.3-1 24V 180 110 22 11 2 98.2-2 1. 0 Bar 73.7-1.8 4 200 1 4 - 2 0 0 11 5.0 211 8 100 - 50 0 0 11 5.0 1304 5 1 - 0 99 0 24V 194 5 8-2 40 0 24V 245 3 4-1 33 0 1.0 Bar 34.4 0 5 58 1 210-TNTC 0 0 106 160 120-12 92-2 9 6. 66 68 6 4-3 50-1 94 2 60-4 0 0 24V 32 110 90-70 27 1. 0 Bat Comments 1,2 and 3 were fogged separately in chillers with 30 minutes intervals. Chillers were not in operation. After fogging, carcasses were retumed to original chillers. Example 2:<BR> Microcidal Effect of Anolyte on Surfaces and Equipment Surface area Before cfu/24cm2 After cfu/24cm2 Table 1 3 4 Scale 125 27 Floor 33 2 Table 2 31 2 Wall 0 0 Hands 21 0 Saw (Only anolyte was used) 7 0 Table(Only anolyte was used) 10 0 Example 3: (Calf Carcasses)<BR> A. Trial Carcasses Direct fogging in chiller with interrupted air circulation<BR> during the fogging process<BR> CFU/10cm2-Total Aeroblc Count Petri film Before 1 x 2x 3x 4x V1Right 168 38 22 18 8 Left 62 0 V2 Right 58 33-2 4 Left 59 18 V3 Right 330 63 25 0 106 Left 123 2 V4 Right 156 56 58 8 154 Left 140 20 V5 Right 220 72 78 19 130 Left 47 12 V6 Right 175 112 110 16 160 Left 46 18 Mean R 185 62 59 11 94 L 79 12 % Decrease-62-68-94-51 <BR> Comments:<BR> The fourth Swab was on the side of the triceps cut where all carcasses had been<BR> pushed by hand and were therefore more contaminated than adjoining surfaces.<BR> <P>All swabs were incubated at 37° C for 48 hours<BR> Coliform counts were negligible on all carcasses B. Negative Control: Indirect fogging of carcasses that were present in the<BR> chiller, during the time of the experiment. Only final<BR> carcass counts on similar locations as the trials were taken. # CFU/l0cm 1 17 2 24 3 5 4 55 5 68 6 14 7 3 Mean 27 Example 4: Woolworths Trial 800 lamb carcasses Results: Treatment with Anolyte Carcase # Before treatment After 2na fogging After 4th fogging TPC Coliform E. coli TPC Coliform E. coli TPC Coliform E. coli B33537 180 0 0 0 1 0 B28392 28 0 0---0 0 0 B29673 27 0 1 9 0 0 5 0 0 B30680 19 0 0 0 0 0 0 0 0 B32522 190 14 0---0 0 0 B29535 3 0 0 4 0 0 0 0 0 B28258 18 0 2 5 0 0 1 0 0 B29602 600 0 0---3 0 0 B29505 23 0 0 8 0 0 2 0 0 B28659 25 0 0 - - - 0 0 0 Total 1113 14 3 26 0 0 11 1 0 Man/111.3 1.4 0.3 5.2 0 0 1.1 0.1 0 20cm² Control group: Carcase Before After chilling 24 hrs # Chilling TPC Coliform E. coli TPC C32592 21 6 0 17 C28363 38 0 0 27 C29469 11 23 0 15 C32540 84 2 0 166 C28309 17 0 0 48 C29137 614 0 0 228 C28588 9 0 0 123 C330390000 C28333 38 1 1 179 C30032 2 0 0 0 TOtal 834 32 803 Mean/83 3.2 0 80 20cm2 = Further swabs were taken on the shoulder of 5 chilled and fogged carcases (after the 4h fogging).

Carcase# TPC 4BS1 1 4BS2 3 4BS3 0 4BS4 6 4BS5 6 Total 16 Mean/20cmz 3.2